Add the proper constant to each binomial so that the resulting trinomial is a perfect square trinomial. Then factor the
trinomial.
-$x ^ { 2 } - 4 x +$______
A) $x ^ { 2 } - 4 x + ( - 16 ) = ( x - 4 ) ^ { 2 }$
B) $x ^ { 2 } - 4 x + \underline { 4 } = ( x - 2 ) ^ { 2 }$
C) $x ^ { 2 } - 4 x + ( - 4 ) = ( x - 2 ) ^ { 2 }$
D) $x ^ { 2 } - 4 x + \underline { 16 } = ( x - 4 ) ^ { 2 }$

Question

Quizplus · Accepted Answer

To form a perfect square trinomial from $x^2 - 4x$, we need to add the square of half the coefficient of $x$. Half of $-4$ is $-2$, and $(-2)^2 = 4$, making $x^2 - 4x + 4$ a perfect square trinomial that factors to $(x - 2)^2$.

Add the Proper Constant to Each Binomial So That the Resulting