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

Answer:
To complete the square you must split the b term in half, then square that answer.
6 is the b term, half of 6 is 3, 3 squared is 9. You will add 9 to both sides of x^2 + 6x = 15
x^2 + 6x + 9 = 24
Answer:
(x+3)² = 24 is the complete square.
Step-by-step explanation:
We have given equation
x² + 6x = 15
We have to complete the square.
For this we split the second term of equation.
x²+(2)(3)(x) = 15
We have to add the square of 3 on both sides of equation.
So, the equation becomes:
x²+(2)(3)x+3²= 15 + 3²
(x+3)² = 15 + 9
(x+3)² = 24
This is the complete square of given expression.