1) (a+3)×(b-7)=ab-7a+3b-21
3) (a-5)×(11-b)=11a-ab-55+5b
5) (x-4)×(x+8)=x^2+8x-4x-32=x^2+4x-32
7) (x-5)×(9-х)=9x-x^2-45+5x=14x-x^2-45
9) (8+3x)×(2y-1)=16y-8+6xy-3x
11) (2a-1)×(3a+7)=6a^2+14a-3a-7
13) (3a²-1)×(2x+ 1)=6a^2 x+3a^2-2x-2
15) (3x²-1)×(2x²+1)=6x^4+3x^2-2x^2-1=6x^4+x^2-1
17) (a+2)×(a²-a-3)=a^3-a^2-3a+2a^2-2a-6
19) (5b-1)×(b²-5b+1)=
5b^3-10b^2+5b-b^2+5b-1
21) 2 (b+1)×(b+3)=2(b^2+3b+b+3)=2B^2+6b+2b+6
23) -8 (y-1)×(y+5)=-8(y^2+5y-y-5)=-8y^2-48y+8y+40
25) (m²-m-1)×(m²+m+1)=m^4-2m-1
27) (x+1)×(x⁴-x³+x²-x+1)=x^5-x^4+x^3-x^2+x+x^4-x^3+x^2-x+1
29) (y+3)×(y-5)×(y²+2y-15)=(y^2+2y-15) (y²+2y-15)=(y²+2y-15)^2