Question

What number must i add to complete the square x^2+8x=-3

Answer 1

16

Explanation:

(b/2)^2

(8/2)^2 = (4)^2 = 16

(x^2+8x+16) = -3+16

(x+4)^2 = 13

so on so forth, but basically you add 16 which completes the square