Verified answer

simplify a little

(10x)(x^2+3)^4(x-2)^4 + (20)(x^2+3)^5(x-2)^3

Factor out the common terms which would be 10, (x^2+3)^4 and (x-2)^3

that would give you

(10)(x^2+3)^4(x-2)^3 [ x(x-2) + 2(x^2+3)]

if your instructor wants you to simplify then,

(10)(x^2+3)^4(x-2)^3 [3x^2-2x+6]