Odpowiedź:
5xy-4x+8y-6xy+5x-xy= -2xy+x+8y
2.
5x +( 2x-7) -9x-( -3x+8)+20-8x= 5x +2x -7 -9x +3x-8+20-8x= -7x +13
-9z -( 4-3z)- 8y-(-7z+8y) +(-2y-7)= -9z -4+3z -8y+7z-8y -2y-7= z -18y-11
3.
x= -2 ; y=3
9y-(7y+x)+ (6x-7y)= 9y -7y -x+ 6x-7y= 9*3-7*3- (-2) +6*(-2)-7*3=27 -21-12-21=
=29- 54= - 25
Szczegółowe wyjaśnienie:
