(5х-4у)+(7х+у)=(5х+4у)-(7х-у)=13х2 - (3-5х+х2)=

Question

(5х-4у)+(7х+у)=
(5х+4у)-(7х-у)=
13х2 - (3-5х+х2)=

Answer 1

1) 5x-4y+7x+y=12x-3y;
2) 5x+4y-7x+y=5y-2x;
3) 13x2-3+5x-x2=12x2+5x-3