1; 10*(m+5)+2*(-2m+3n)=10m+50-4m+6n=6m+6n+50
2; 7x*(4y-x)+4x(x-7y)=28xy-7x²+4x²-28xy=4x²-7y²
3; 4a (7x-1)-7(4ax+?)=28ax-4a-28ax-7?=-4a-7?
4; 3a-2a(5+2a)+10a=3a-10a-4a²+10a=-4a²+3a
5;5a(6a+3b)-6a(5b-2a)=30a^2+15ab-30ab+12a^2=42a^2-15ab=3a(14a-5b)
6;8m(m+n)-3n(2m-4n)=8m^2+8mn-6nm+12n^2=20n^2+2mn=2n(10n+m)
