Write the square for the expression x^2 - 16x +____. Write the new expression as a binomial squared.

Question

Complete the square for the expression x^2 - 16x +____. Write the resulting expression as a binomial squared. 

A:       (x - 8)^2

B:       (x + 8)^2

C:       (x + 16)^2

D:       (x - 16)^2

 

 I have had a lot of trouble on this and I can't figure it out.

 

Answer 1

x^2-16x+64=(x-8)^2 (answer A). To complete a square you halve the coefficient of the middle term and square it. If the coefficient is minus there will be a minus between x and the number which is half the middle coefficient number. Otherwise it's plus.