А)5а+7б-2а-8б=3a-1
Б)3(4*x+2)-5=12x+1
6(0,5х-1,5)-4,5х-8 при х= 2/3 =-18
1) xy-5x+3y-15=x(y-5)+3(y-5)=(x+3)(y-5)
2) x^{2}-3x+2x-6=x(x-3)+ 2(x-3)=(x+2)(x-3)
x^{2}-3x+2x-6=x(x+2)-3(x+2)=(x-3)(x+2)
3) xy+4y-3x-12=(x+4)(y-3)
4) x^{3}+7x^{2}-xy-7y=x^{2}(x+7)-y(x+7)=(x^{2}-y)(x+7)