Question

napisz jak najprostszej postaci:

a) (x+1)(x-2)+(x+2)(x-1)

b) (5k+n)(k-2n)-k(4k+n)

c) (4y+3)(y-2)-2y(4-2y)

d) -(3c-2)(c-1)-c(c-2)

Answer 1

a) (x+1)(x-2)+(x+2)(x-1)=x²+x-2x-2+x²+2x-x-2=2x²-2

b) (5k+n)(k-2n)-k(4k+n)=5k²+kn-10kn-2n-4k²-kn=k²-2n²-10kn

c) (4y+3)(y-2)-2y(4-2y)=4y²+3y-8y-6-8y+4y²=8y²-13y-6

d) -(3c-2)(c-1)-c(c-2)=-(3c²-2c-3c+2)-c²+2c=-3c²+2c+3c-2-c²+2c=-4c²+7c-2