Odpowiedź:
a) m²-2m+mn-2n+m²+m-mn-n=
2m²-m-3n
b)9x²-6xy+3x-6x+4y-2-8x²+12xy-4x=
x²+6xy-7x+4y-2
c)(3m+3)(n-2)+2(nm-2n+m-2)=
3mn-6m+3n-6+2nm-4n+2m-4=
5mn-4m-n-10
d)(x²+x)(x+2)-x(x²-2x-x+2)=
x³+2x²+x²+2x-x³+2x²+x²-2x=6x²
