Degree 3 polynomial with zeros 3, 5, and -4

Answer 1

f(x) = (x-3)(x-5)(x+4)

Just take each zero, change it's sign and add it to x

then multiply them all together

Set it = 0, set each factor = 0, solve for x and you get x=3, x=5, x=-4

Multiply the factors together if you want to get a 3 degree polynomial

(x-3)(x-5) = x²-8x+15. Now multiply that by x+4 to get an expressly 3 d poly x³-4x²-17x+60