Answer:
{-5, 3}
Explanation:
7 is a factor common to all three terms of this polynomial function. Thus, after the first attempt to factor it, we have 7(x^2 + 2x - 15). The quadratic factors into (x + 5)(x - 3). Setting these = to zero individually, we get
x + 5 = 0, or x = -5, and
x - 3 + 0, or x = 3
Thus, the zeros of the given f(x) =7x2 + 14x − 105 are {-5, 3}.