Answer:
(c) 25/4
Step-by-step explanation:
A perfect square trinomial is obtained by "completing the square." The constant in a perfect square trinomial is the square of half the x-coefficient.
Square of a binomial
A "perfect square trinomial" is the square of a binomial.
(x +a)² = x² +2ax +a²
Of note here is that the constant (a²) is the square of half of the x-term coefficient:
((2a)/2)² = a²
Completing the square
The given expression (x² +5x) has an x-term coefficient of 5. The square of half that is ...
(5/2)² = 25/4
The constant that must be added to make x² +5x into a perfect square trinomial is 25/4.
(x² +5x) +25/4 = x² +5x +25/4 = (x +5/2)²
