What number must you add to complete the sqaure? x^2+2x=-1

1

Step-by-step explanation:

By adding 1 on both sides we get:

By adding such we get on the left a perfect square trinomial (a trinomial that is the result of squaring a binomial):

To decide what to add, understand what is the result of squaring a binomial of the form:

In your case, 2*c*x is "2x" therefore the value of c must be 1.

so to complete the square you need to add which will result in

d) 48

step-by-step explanation:

16,32,48,64,80,96,112,128,144,160,176,192,208,224,240,256,272,288,304,320,336