Question

What number must you add to complete the square?
x2 + 6x = 15

Answer 1

Answer: 9

Explanation:

x2+6x+(3)2=15+(3)2

x2+6x+9=24

(x+3)2=24

x=±2√6−3

x=±2√6−3 is final answer

Answer 2

Add 9 to each side

Explanation:

x^2 + 6x = 15

Take the coefficient of x

6

Divide by 2

6/2 =3

Square it

3^2=9

Add 9 to each side

x^2 + 6x+9 = 15+9

(x+3) ^2 = 24