Given x^2 -4x+4 is a factor of the polynomial 2x^4 - 11x^3 +68x-80, completely factor the polynomial using algebraic methods.

2x^4-11x^3+68x-80

2x^4-4x^3-7x^3+14x^2-14x^2+28x+40x-80

2x^3(x-2)-7x^2(x-2)-14x(x-2)+40(x-2)

(x-2)(2x^3-7x^2-14x+40)

(x-2)(2x^3-4x^2-3x^2+6x-20x+40)

(x-2)(2x^2(x-2)-3x(x-2)-20(x-2))

(x-2)(x-2)(2x^3-3x-20)

(x-2)(x-2)(2x^2+5x-8x-20)

(x-2)(x-2)(x(2x+5)-4(2x+5))

(x-2)(x-2)(2x+5)(x-4)

(x-2)^2(2x+5)(x-4)