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Use the quadratic formula to solve these equations, showing work. Of course, every equation's value of x is independent from the rest.

(x^2) + 4x - 2 = 0

-6(x^2) + 3x + 2 = 3

-(x^2) +1 = -5(x^2) + 4x

2(x - 3)^2 = -2x + 9

 Dec 5, 2014

Best Answer 

 #1
avatar+118587 
+18

Come on Shadew, we are not here to do all your homework for you.

The first one can just get plugged straight into the quadratic formula  a=1,  b=4 and c=-2

The others you need to simplify so that they are in the form  $$ax^2+bx+c=0$$     first.

 

this might help

http://www.youtube.com/watch?v=O8ezDEk3qCg

 Dec 5, 2014
 #1
avatar+118587 
+18
Best Answer

Come on Shadew, we are not here to do all your homework for you.

The first one can just get plugged straight into the quadratic formula  a=1,  b=4 and c=-2

The others you need to simplify so that they are in the form  $$ax^2+bx+c=0$$     first.

 

this might help

http://www.youtube.com/watch?v=O8ezDEk3qCg

Melody Dec 5, 2014
 #2
avatar+59 
+10

Well, to be fair, that isn't all of it.

But I seriously thought the point of this site was to get help with math homework. Granted, I could (and should) have just asked for you guys to answer one and then applied the steps to the rest.

 Dec 5, 2014
 #3
avatar+128079 
+5

Shadew.....let us know if you have trouble putting any of them in S.F.......once you do that....it's just "plug and play," basically.......

 

 Dec 5, 2014
 #4
avatar+59 
+5

Well, if you wouldn't mind helping w/ one of those two-sided ones, that'd be great. Is it done the same way, just using the formula on both sides?

 Dec 5, 2014
 #5
avatar+118587 
+5

I'll take it Chris :)

 Dec 5, 2014
 #6
avatar+128079 
+15

No....we want everything on the same side  - I prefer the left side, myself

For instance....this one...

-(x^2) +1 = -5(x^2) + 4x        add 5x^2 to both sides and subtract 4x from both sides

4x^2 - 4x + 1 = 0      so...a = 4 b = -4 and c = 1     (got it ???)

(Actually....I wouldn"t even use the Q formula on this one....it can be factored and solved directly.....!!!.......but if that's what they're asking you to do.....)

 

 Dec 5, 2014
 #7
avatar+118587 
+15

You have to get them all to one side an  = 0 first.

eg

$$\\2(x - 3)^2 = -2x + 9\\
2(x - 3)(x-3) = -2x + 9\\
2(x^2-6x+9) = -2x + 9\\
2x^2-12x+18 = -2x + 9\\
2x^2-12x+2x+18-9 = -2x+2x + 9-9\\
2x^2-10x+9 = 0\\\\
a=2,\;\; b=-10,\;\; c=9$$

 Dec 5, 2014
 #8
avatar+59 
+10

Huh. Alrighty then. Thanks very much, guys.

 Dec 5, 2014
 #9
avatar+26364 
+10

Use the quadratic formula to solve these equations

https://www.youtube.com/watch?v=ZywdPuXR0S0

nice song about quadratic formula 

 Dec 5, 2014

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