The polynomial of degree 3, P(x), has a root of multiplicity 2 at x=2 and a root of multiplicity 1 at x=−2. The y-intercept is y=−2.4; Find a formula for P(x).

Answer 1

P(x) = (x-2)²(x+2) -2.4

Answer 2

To get a root of 2, you can only have x-2=0 and for -2 you'd need x+2=0. The first has a multiplicity of 2 which means that it happens twice (x-2)(x-2) with the other being (x+2). Since there are 3 Xs, the polynomial is degree 3. Multiply (x-2)(x-2)(x+2) together and you will have P(x).