Question

Identify the # that needs to be added to both sides of the equation x(squared)-8x=-15

Answer 1

to complete the square

Answer 2

x^2-8x=-15 Add +15 to both sides and you get:
x^2-8x+15=0
(x-5)(x-3)=0
x-5=0
x=5

x-3=0
x=3

Therefore, x=3 and x=5