Algebra
posted by Anonymous .
Hi! I just want you to check if my answers are correct.
Factor the expressions:
1. 15a^2(b2)^2 + 20a^3(b2)^3 = my answer is 5a^2(b2)^2 [3 + 4a(b2)]
2. 18p^2q^3 (r6)+ 24(r6) = my answer is 6(r6)[3p^2q^3 + 4]
3. 24(xy)^2 + 48(yx)  72(xy)^3 = my answer is 24[(xy)^2 + 2(yx)  3(xy)^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. :)

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. 
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)