Answer:
ur answer would be B, because you do 45-15 x 4
Step-by-step explanation:
Answer:
16
Step-by-step explanation:
The number to add on both sides to complete the square is the square of the numerical coefficient that accompanies the term in "x", divided by 2.
That is in our case: 
Therefore:

That way the left hand side of the equation becomes the perfect square of the binomial: (x+4).
You can also prove that such is correct by developing the square of the binomial:

H=4. Solving the equation gives you two answers, 4 and -0.5 and since you can't logically have negative height, 4 is the only legitimate answer that is realistic.