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please help he answer this math question. I know the answer, just not how to get it. If you could please help me explain each step I would be most appreciative.

 

2x2+2x=60

solve for x 

you should get two answers. 

FieryJade122  Feb 16, 2018
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3+0 Answers

 #1
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Solve for x:

2 x^2 + 2 x = 60

 

Divide both sides by 2:

x^2 + x = 30

 

Add 1/4 to both sides:

x^2 + x + 1/4 = 121/4

 

Write the left hand side as a square:

(x + 1/2)^2 = 121/4

 

Take the square root of both sides:

x + 1/2 = 11/2 or x + 1/2 = -11/2

 

Subtract 1/2 from both sides:

x = 5 or x + 1/2 = -11/2

 

Subtract 1/2 from both sides:

x = 5         or          x = -6

Guest Feb 16, 2018
 #2
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Thank you so much! I am failing in math and this means so much!!!

FieryJade122  Feb 16, 2018
 #3
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An alternative method you can use especially if you are familiar with factoring quadratic trinomials is the following 

 

moving on from x+ x = 30 you move the 30 across to the left hand side 

 

x2  +  x  -  30 =  0

 

then  (x+6)(x-5) = 0

 

conclusion : if 2 factors multiply to give 0 then either can be 0

 

ie x+6 =0  or  x-5=0  

 

therefore  x=-6 or x=5

Guest Feb 16, 2018

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