1.
а) (8+3х)(2y-1)=16y-8+6xy-3x
б)(2a-1)(3a+7)=6a²+12a-7
в)(5x-2y)(4x-y)=20x²-13xy+2y²
г)(a-2)(a²-3a+6)=a³-3a²+6a-2a²+6a-12=a³-5a²+12a-12
2.
а)5x+5y=5*(x+y)
б)-6ab+9b²=-3b*(2a-3b)
в)8mn-4m²=4m*(2n-m)
3.
а)(x²+xy-y²)(x+y)=x³+x²y+x²y+y²x-y²x-y³=x³-y³+2x²y
б)(5x-2)(x²-x-1)=5x³-10x²-5x-2x²+2x+2=5x³-12x²-3x+2
4.
а)mx+my+6x+6y=m*(x+y)+6*(x+y)=(m+6)*(x+y)
б)7a-7b+an-bn=7*(a-b)+n*(a-b)=(7+n)*(a-b)
в)xb+xc+3b+3c=x*(b+c)+3*(b+c)=(x+3)*(b+c)
5.
7-4*(3x-1)=5*(1-2x)
7-12x+4=5-10x
-2x=-6|:(-2)
x=3
Ответ:3.