Which of the binomials below is a factor of this trinomial?

x2 - 13x + 42

a. x2 + 12

b. x + 84

c. x + 7

d. x - 7

So this is how we factor the given trinomial above.
The first thing we are going to do is to find the factors of 42, and this factors when added should be equal to -13. So those numbers would be -7 and -6.
Therefore, the factors would be (x-7)(x-6). When you check this, you will get x2 - 13x + 42. Therefore, the answer for this question would be option D. Hope this answer helps.