Question

Zapisz w jak najprostrzej 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)=x²-2x+x-2+x²-2+2x-2=2x² +x -6
b)(5k+n)(k-2n)-k(4k+n)=5k²-10kn+nk-2n²-4k²-kn=k²-2n² c)(4y+3)(y-2)-2y(4-2y)=4y²-8y+3y-6-8y+4y²=8y²+3y-6

d)-(3c-2)(c-1)-c(c-2)=-(3c²-3c-2c+2)-c²+2c=-3c²+5c-2-c²+2c=-4c²+7c-2

Answer 2

A).(x+1)(x-2)+(x+2)(x-1)=x²-2x+x-2+x²-x+2x-2=2x²-4
b).(5k+n)(k-2n)-k(4k+n)=5k²-10kn+kn-2n²-4k²-kn=k²-10kn-2n²
c).(4y+3)(y-2)-2y(4-2y)=4y²-8y+3y-6-8y+4y²=8y²-13y-6
d).-(3c-2)(c-1)-c(c-2)= -3c²+3c+2c-2-c²+2c= -4c²+7c-2