Final answer:
The polynomial factors x + 7 and x - 3 equal zero when x is -7 and 3, respectively. Therefore, the correct answer is B. -7 and 3.
Step-by-step explanation:
If the factors of a polynomial are x + 7 and x - 3, to find the values of x that make the polynomial 0, you set each factor equal to zero and solve for x.
For the factor (x + 7), setting it to zero gives:
x + 7 = 0
x = -7
For the factor (x - 3), setting it to zero gives:
x - 3 = 0
x = 3
Therefore, the values of x that make the polynomial 0 are -7 and 3.