x+y+z=
x=2a-2b+1
y=-a+b+3
z=-5(a-b)=-5a+5b
A) (2a-2b+1)+(-a+b+3)+(-5a+5b)=
2a-2b+1+-a+b+3+-5a+5b=
-4a+4b+4
B) 2x+3y-z=
2(2a-2b+1) +3(-a+b+3)-(-5a+5b)=
4a-4b+2-3a+3b+6+5a-5b=
6a-6b+8
C)-2(x+y)+3(-z)=
-2(2a-2b+1+-a+b+3)+3(-5a+5b)=
-2(a-b+4)-15a+15b=
-2a+2b-8-15a+15b=
-17a+17b-8
D) x·y=
(2a-2b+1)·(-5a+5b)=
-10a+10ab-10ab-10b-5a+5b=
-15a+15b
E)-y·z=
-(-a+b+3)·(-5a+5b)=
(a-b-3)(-5a+5b)=
-5a²+5ab+5ab-5b²+15a+15b
sper ca te-am ajutat
