Find the values of m and n if y^4 + my^3 + 2y^2- 3y + n is divisible by y^2-1

Answer 1

Just do the division. The remainder is

(m-3)y + (n+3)

To be divisible, the remainder must be zero, so that means

m=3 and n = -3.

Check:
y^4 + 3y^3 + 2y^2 - 3y - 3 = (y^2-1)(y^2+3y+3)

Answer 2

Find the value of m and n if y2 - 1 is a factor of y4 + my + 2y2 - 3y + n.