Official Everybody Edits Forums

AllenCaspe9510

Member

From: Heart Locket

Joined: 2018-03-24

Posts: 901

Website

Annoying Math Problems

Today, My teacher was sort of, tricked us and used confusing explanation on "Solving Quadratic Equations by Factoring"
Then I got a Score of 2/10, The Answers I saw was like, where did he even get this and he even didn't even tell us.
So can anyone help me to try to do this?

 

Confusing Problem

▼Hidden text

2x + 1 = 0
2x = -1 (How is this even possible?)
x= -1/2

Ill send the full question later

---

I Animate Stuff

LukeM

Member

From: England

Joined: 2016-06-03

Posts: 3,009

Website

Re: Annoying Math Problems

The general rule for algebra is that you can do anything you can do to normal numbers as long as you do them to both sides, so if you had x = y then you could multiply both sides by 2 to get 2x = 2y, or subtract 2 to get x - 2 = y - 2.

In this case you are subtracting one from both sides, which gives you 2x + 1 - 1 = 0 - 1, which you can then simplify to get 2x = -1, effectively 'moving' the 1 from one side to the other.

You can then just divide by two to get 2x / 2 = -1 / 2, which gives x = -1/2.

Hope this helps

Anatoly

Guest

Re: Annoying Math Problems

For x = y, x and y in set of real numbers you can get ...

1. ax = ay

2. x + a = y + a

3. x^a = y^a

4. a^x = a^y

... for any a in set of real numbers. That means that you can:

1. Add and subtract one number from both sides of an equation.

2. Multiply and divide by any number not zero from both sides of an equation.

3. Take any power or root from both sides of an equation.

Edit:

2x + 1 = 0
2x + 1 + (-1) = -1
2x = -1
2x * (1/2) = -1 * (1/2)
(2x/2) = -1/2
x = - 1/2

2b55b5g

Formerly 2B55B5G TNG

Joined: 2016-08-27

Posts: 3,005

Re: Annoying Math Problems

What that’s easy.

---

she/her

also known as DevilCharlotte

search 2bisniekitastan if you wanna find my worlds on ArchivEE

pfp: https://picrew.me/image_maker/1272810

AllenCaspe9510

Member

From: Heart Locket

Joined: 2018-03-24

Posts: 901

Website

Re: Annoying Math Problems

Heres the Full question
4x^2 + 4x + 1 = 0

Thanks for the answer

---

I Animate Stuff

Anatoly

Guest

Re: Annoying Math Problems

Heres the Full question
4x^2 + 4x + 1 = 0

Thanks for the answer

4x^2 + 4x + 1 = (2x)^2 + 2 * (2x) * (1) + (1) = (2x+1)^2

(2x+1)^2 = 0
(2x+1)^2^(1/2) = 0^(1/2)
|2x+1| = 0

ZeldaXD

EE Homeboy

From: Cyprus

Joined: 2015-02-15

Posts: 1,539

Website

Re: Annoying Math Problems

Heres the Full question
4x^2 + 4x + 1 = 0

Thanks for the answer

You have to know the formula for quadratic equations
That is, for the equation
ax^2 + bx + c = 0
x = (-b +- sqrt(b^2 - 4ac))/2a

So in your equation
x = (-4 +- sqrt(16 - 4*4*1))/8
x = (-4 +- sqrt(0))/8
x = -4/8
x = -1/2

---

bunglybongle

Guest

Re: Annoying Math Problems

what i was taught was:
5x - 4 = 2x + 8
take away the small x thing from the big x thing
3x - 4 = 8
then do stuff
3x = 8 + 4
then you divide the answer to the 8+3 by the number x thing
x = 12/3
tada you done fam
x = 4

peace

Member

From: admin land

Joined: 2015-08-10

Posts: 9,226

Re: Annoying Math Problems

Heres the Full question
4x^2 + 4x + 1 = 0

Thanks for the answer

i would use the metoh for 'guessing the answer'  guess an answer you think is right and fill it in the X's try until you found the answe is what works with an ^ sign otherwise lukems thing works in your first question whic is ez

---

thanks hg for making this much better and ty for my avatar aswell

MWstudios

Member

From: World 4-2

Joined: 2018-04-06

Posts: 1,331

Re: Annoying Math Problems

Heres the Full question
4x^2 + 4x + 1 = 0

Thanks for the answer

This thing, how is it called

I know you use this for those questions

---

Time before becoming a Member - Leaderboard
1. Whirl - 9 months
2. KirbyKareem - 8 months
3. pwnzor - 2.4 months
4. MWstudios - 2 months
5. ILikeTofuuJoe - 1.5 months
Piskel is the best GIF maker I've seen
HG's signature for me - Anatoly's signature for me
The Mashed Potatoes Song - The longest post on EE forums - Play my Minesweeper

AllenCaspe9510

Member

From: Heart Locket

Joined: 2018-03-24

Posts: 901

Website

Re: Annoying Math Problems

Heres the Full question
4x^2 + 4x + 1 = 0

Thanks for the answer

This thing, how is it called
https://imgur.com/wSRGUj2.png
I know you use this for those questions

Uhh... No, I might see it sometime

---

I Animate Stuff

Anatoly

Guest

Re: Annoying Math Problems

what i was taught was:
5x - 4 = 2x + 8
take away the small x thing from the big x thing
3x - 4 = 8
then do stuff
3x = 8 + 4
then you divide the answer to the 8+3 by the number x thing
x = 12/4
tada you done fam
x = 3

Why 3? Why do you divide by 4? X = 12/3 -> x = 4

MWstudios

Member

From: World 4-2

Joined: 2018-04-06

Posts: 1,331

Re: Annoying Math Problems

Heres the Full question
4x^2 + 4x + 1 = 0

Thanks for the answer

This thing, how is it called
https://imgur.com/wSRGUj2.png
I know you use this for those questions

Uhh... No, I might see it sometime

It works like this (or at least how I remember it):

---

Time before becoming a Member - Leaderboard
1. Whirl - 9 months
2. KirbyKareem - 8 months
3. pwnzor - 2.4 months
4. MWstudios - 2 months
5. ILikeTofuuJoe - 1.5 months
Piskel is the best GIF maker I've seen
HG's signature for me - Anatoly's signature for me
The Mashed Potatoes Song - The longest post on EE forums - Play my Minesweeper

Minimania

Moderation Team

From: PbzvatFbba 13

Joined: 2015-02-22

Posts: 6,395

Re: Annoying Math Problems

4x^2 + 4x + 1 = 0

This thing is called a quadratic equation. Quadratic equations are base 2 (meaning the leading factor is to the power of two). They're written like this... ax^2 + bx + c = 0.

In order to solve these, there are a few methods, but the most reliable way to solve these is by using the quadratic formula... the thing MWStudios posted earlier...

In order to use the quadratic formula, just "plug in" the numbers from the original equation into where it belongs on the formula, and solve it.

ax^2 + bx + c = 0.

This is how they are written

4x^2 + 4x + 1 = 0

This is the equation you're solving... a=4, b=4, and c=1, so plug those numbers into the equation and solve.

---

Click the image to see my graphics suggestions, or here to play EE: Project M!

LukeM

Member

From: England

Joined: 2016-06-03

Posts: 3,009

Website

Re: Annoying Math Problems

Just FYI the OP's question specifically said you had to solve it by factoring, so you can't just throw the formula at it and write down what you get, you need to try to get it to the form (ax + b)(cx + d) = 0, usually just by inspection, then you can say that either side must be 0, so x = -b/a or -d/c.

bunglybongle

Guest

Re: Annoying Math Problems

what i was taught was:
5x - 4 = 2x + 8
take away the small x thing from the big x thing
3x - 4 = 8
then do stuff
3x = 8 + 4
then you divide the answer to the 8+3 by the number x thing
x = 12/4
tada you done fam
x = 3

Why 3? Why do you divide by 4? X = 12/3 -> x = 4

ok sorry i did a dumb thing i made a typo

peace

Member

From: admin land

Joined: 2015-08-10

Posts: 9,226

Re: Annoying Math Problems

what i was taught was:
5x - 4 = 2x + 8
take away the small x thing from the big x thing
3x - 4 = 8
then do stuff
3x = 8 + 4
then you divide the answer to the 8+3 by the number x thing
x = 12/3
tada you done fam
x = 4

what i was though was
5x-4=2x+8
3x-4=8
3x=12
12/3x=4
x=4
or
5x-4=2x+8
-4=-3x+8
-12=-3x
-12/-3x=4
x=4
basically get all the variables in this cases the X's on one side by adding/subtractign them evenly (check if positive or  negative numbers!) then get all looose nubmbers on otther side then its an easy division (or not) tehn you COULD checkyourself by putting you answer onthe X's and get 5x-4=2x+8      5*4-4=16 2*4+8=16 = even its just like a weightscale thaking blocks form 1KG for loose numbers and like other blocks or objects for the X take away even from bto sdies and tis still even (doesntwork when negative numbers but its still same ;p)

---

thanks hg for making this much better and ty for my avatar aswell

AllenCaspe9510

Member

From: Heart Locket

Joined: 2018-03-24

Posts: 901

Website

Re: Annoying Math Problems

How about solving Quadratic Equations by Completing the square for binomial and trinomial?
I was also confused about those

Three of this is quite annoying to understand
[] (h - 3/5)^2 = 1/2

[] s^2 + 3/4 s + 9/64

[] h^2 - 3/4 h + ___?

Edit:
   I'm not doing this for my assignment, I need a formula :/

---

I Animate Stuff

Slabdrill

Formerly 12345678908642

From: canada

Joined: 2015-08-15

Posts: 3,402

Website

Re: Annoying Math Problems

ax^2 + bx + c
= a(x^2 + bx/a) + c
= a(x^2 + bx/a + (b/2a)^2) - b^2/4a + c
= a(x + (b/2a))^2 - b^2/4a + c

Which gives you a quadratic equation in vertex form (y=a(x-h)^2+k, where h = -b/2a, k = -b^2/4a+c)

notes:
a(b/2a)^2 = a(b^2/4a^2) = b^2/4a
x^2 + 2xy + y^2 = (x+y)^2 (where y = b/2a)
If you only care about your final answer (your math teacher is bad if this is the case), you only really need to know the last line in that equation.

---

This was a nice refresher. I haven't needed to do basic math like this for about 5 months.
If you need more help, I'd recommend Khan Academy.

---

suddenly random sig change

Gosha

Member

From: Russia

Joined: 2015-03-15

Posts: 6,211

Re: Annoying Math Problems

To help you visualize math use https://www.desmos.com/calculator

if you want to check your answer, plug in the formula and you'll get a visualized result

peace

Member

From: admin land

Joined: 2015-08-10

Posts: 9,226

Re: Annoying Math Problems

To help you visualize math use https://www.desmos.com/calculator

if you want to check your answer, plug in the formula and you'll get a visualized result
https://gosha.eejesse.net/files/7910468d.png

nice calcultor

---

thanks hg for making this much better and ty for my avatar aswell

MWstudios

Member

From: World 4-2

Joined: 2018-04-06

Posts: 1,331

Re: Annoying Math Problems

To help you visualize math use https://www.desmos.com/calculator

if you want to check your answer, plug in the formula and you'll get a visualized result
https://gosha.eejesse.net/files/7910468d.png

Is that a Geogebra bootleg?

---

Time before becoming a Member - Leaderboard
1. Whirl - 9 months
2. KirbyKareem - 8 months
3. pwnzor - 2.4 months
4. MWstudios - 2 months
5. ILikeTofuuJoe - 1.5 months
Piskel is the best GIF maker I've seen
HG's signature for me - Anatoly's signature for me
The Mashed Potatoes Song - The longest post on EE forums - Play my Minesweeper