Odpowiedzi

2009-12-10T19:27:16+01:00
A)
(m+n)(m-2)+(m-n)(m+1)=m²-2m+mn-2n+m²+m-mn-n=2m²-m-3n

b)
(3x-2)(3x-2y+1)-4x(2x-3y+1)=9x²-6xy+3x-6x+4y-2-8x²+12xy-4x=x²-7x+6xy+4y-2

c)
3(m+1)(n-2)+2(n+1)(m-2)=(3m+3)(n-2)+(2n+2)(m-2)=3mn-6m+3n-6+2mn-4n+2m-4=5mn-4m-n-10

d)
x(x+1)(x+2)-x(x-1)(x-2)=(x²+x)(x+2)-(x²-x)(x-2)=x³+2x²+x²+2x-(x³-2x²-x²+2x)=x³+2x²+x²+2x-x³+2x²+x²-2x=6x²