Complete the square to make the binomial a perfect square trinomial. $$x ^ { 2 } - 20 x$$
A) $\quad x ^ { 2 } - 10 x + 100$
B) $\quad x ^ { 2 } - 20 x + 100$
C) $\quad x ^ { 2 } - 20 x + 400$
D) $\quad x ^ { 2 } - 40 x + 20$
E) $x ^ { 2 } - 40 x + 100$

Question

Quizplus · Accepted Answer

To complete the square, we need to add the square of half of the coefficient of the linear term. The linear term in this binomial is $-20x$, so half of its coefficient is $-10$. We square this to get $100$. Adding this to the expression gives us $x^2-20x+100$, which is a perfect square trinomial.

Complete the Square to Make the Binomial a Perfect Square x2−20xx ^ { 2 } - 20 xx2−20x

Complete the Square to Make the Binomial a Perfect Square $x ^ { 2 } - 20 x$