6. Which of the following is the factored form of the equation x2 - 10x + 21 = 0?
a. (x – 7)(x - 3) = 0
c. (x + 7)(x-3) = 0
b. (x - 7)(x + 3) = 0
d. (x + 7)(x + 3) = 0
7. What number must be added to make x2 – 15x +_ a perfect square trinomial
335
d.
25
.
125
b.
225
C.
4​