Opuść nawiasy, zredukuj i oblicz wartość liczbową. a) -(2x-2y+2xy)-(4x-2y-xy)= dla x=2, y= -2 b) 6ab-(-3a+2b) +(-9ab-3a+2b)= dla a= -1, b=2 c)-2x-(y-1)-(-x+2)-(2x-1)= dla x=0,1

a)-(2x-2y+2xy)-(4x-2y-xy)=-2x+2y-2xy-4x+2y+xy=-6x+4y-xy -6*2+4*(-2)-2*(-2)=-12-8+4=-16 b)6ab-(-3a+2b) +(-9ab-3a+2b)=6ab+3a-2b+(-9ab)-3a+2b=-3ab -3*(-1)*2=6 c)-2x-(y-1)-(-x+2)-(2x-1)=-2x-y+1+x-2-2x+1=-3x-y -3*0,1-y=-0,3-y

a) =-2x+2y-2xy+4x+2y+xy= =2x+4y-1xy= =2*2+4*(-2)-1*2*(-2)= 4-8-4=-8

a) -(2x-2y+2xy)-(4x-2y-xy)= dla x=2, y= -2 =-2x+2y-2xy-4x+2y+xy=-6x-xy+4y=-6*2-2*(-2)+4*(-2)=12+4-8=8 b) 6ab-(-3a+2b) +(-9ab-3a+2b)= dla a= -1, b=2 =6ab+3a-2b-9ab-3a+2b=-3ab=-3*(-1)*2=6 c)-2x-(y-1)-(-x+2)-(2x-1)= dla x=0,1 =-2x-y+1+x-2-2x+1=-3x-y+2=-3*0,1-y+2=-0,3-y+2=1,7-y c)-2x-(x-1)-(-x+2)-(2x-1)= dla x=0,1 =-2x-x+1+x-2-2x+1=-4x=-4*0,1=0,4