Hi! I just want you to check if my answers are correct.

Question

Factor the expressions:
1. 15a^2(b-2)^2 + 20a^3(b-2)^3 = my answer is 5a^2(b-2)^2 [3 + 4a(b-2)]
2. 18p^2q^3 (r-6)+ 24(r-6) = my answer is 6(r-6)[3p^2q^3 + 4]
3. 24(x-y)^2 + 48(y-x) - 72(x-y)^3 = my answer is 24[(x-y)^2 + 2(y-x) - 3(x-y)^3]
Lastly, -8.4x^3y^4 - 3.6x^2y^5 - 4.8x^4y^3. I don't have an answer for it yet.
Would appreciate your response. Thank you. :)

Answer 1

1. Good but you my want to distribute the parentheses inside the bracket.
2. Good
3. Hint: to out a negative sign in the middle term.

Answer 2

-8.4x^3y^4 - 3.6x^2y^5 - 4.8x^4y^3
Factor out -1.2x^2y^3 to get

-1.2x^2y^3(7xy + 3y^2 + 4x^2)
Rearrange terms to get

-1.2x^2y^3(4x^2 + 7xy + 3y^2)
Now factor that to get

-1.2x^2y^3(x+y)(4x+3y)