The polynomial f(x) has degree 3 if f(-1)=15, f(0)=0, f(1)=5, f(2)=0, then what are the x-intercepts of the graph of f?
From the fact that f(2) = 0 and f(0) = 0, we know that 0 and 2 are both roots/x-intercepts of this graph. Suppose that a is the other root, this gives us:
f(x) = (x - 0)(x - 2)(x - a)
Plugging in 1 for x gives us
f(1) = -1(1 - a)
5 = -1 + a
a = 6
Therefore, the x intercepts, are, 0, 2, and 6.