Question

Solve equation for the x

Answer 1

We can either use the quadratic formula or completing the square.

I'll use the method if completing the square.

x^2 + 10x + 12 = 36

Move the constant over to the other side.

x^2 + 10x = 24

Add (b/2)^2 to both sides.

x^2 + 10x + (10/2)^2 = 24 + (10/2)^2

x^2 + 10x + 5^2 = 24 + 5^2

x^2 + 10x + 25 = 24 + 25

Factor the left side and add the terms on the right side

(x+5)(x+5) = 49

(x+5)^2 = 49

Find the square root of both sides.

x + 5 = +/- 7

Move 5 over to the other side by subtracting it.

x = -5 + -7 = -12

OR

x = -5 - (-7) = 2

So x = -12 or x = 2.