Find the number to add to x^2 + 14x to make it a perfect square trinomial. Write that trinomial as the square of a binomial.
a. add 28; (x+14)^2
b. add 14; (x+7)^2
c. add 49;(x+7)^2
d. add 196; (x+14)^2
To make x^2 + 14x a perfect square trinomial, we need to add the square of half the coefficient of x. In this case, the coefficient of x is 14. Half of 14 is 7. So, we need to add 7^2 = 49 to make it a perfect square trinomial.
Thus, the correct answer is option c. add 49; (x+7)^2.