Multiplication Of Polynomials
1. 7a(5x^2-2xy+y^2-4xy)=
2. -a^4(a^2b^2+2ab-3+6ab+8)=
just use the distributive property, as in
7(3+5) = 7*3 + 7*5
now just plug in 7a for the first, and you get
7a*5x^2 - 7a*2xy + ...
35ax^2 - 14axy + ...
Try that, and if you get stuck, come back and show us where.