Question

A 4th degree polynominal has roots at -2 and 1 and a double root at 5. give a possible equation.

Answer 1

construct the factors from the roots:\[(x-r_1)(x-r_2)(x-r_3)(x-r_4)\]and expand it out

Answer 2

(x + 2)(x - a)(x - b)^2

can you figure values of a and b ?

Answer 3

yes

Answer 4

or ... and this is usually a longer drawn out method

construct 4 equations in 4 unknowns and solve the system