+31 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.
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
An alternative method you can use especially if you are familiar with factoring quadratic trinomials is the following
moving on from x2 + 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
