1) 3a(2-b) = 3a×2 - 3a×b = 5a - 3ab
2) (5a-6b)(6b-5a)= 5a×6b+5a×(-5a) -6b×6b-6b×(-5a)=6b5a-25a-36b+6b5b
3)(x-y)(x+y)(x-y) = (x×x+x×y-y×x-y×y)(x-y)=(x²+xy-yx-y²)(x-y)=
x²×x+x²×(-y)+xy×x+xy×(-y) -yx×x-yx×(-y) -y²×x-y²×(-y)=
x³-x²y+x²y-xy²-yx²-y²x-y²x+y³
1) 3a(2-b) = 3a×2 - 3a×b = 5a - 3ab
2) (5a-6b)(6b-5a)= 5a×6b+5a×(-5a) -6b×6b-6b×(-5a)=6b5a-25a-36b+6b5b
3)(x-y)(x+y)(x-y) = (x×x+x×y-y×x-y×y)(x-y)=(x²+xy-yx-y²)(x-y)=
x²×x+x²×(-y)+xy×x+xy×(-y) -yx×x-yx×(-y) -y²×x-y²×(-y)=
x³-x²y+x²y-xy²-yx²-y²x-y²x+y³