1. а) (c+2)(c-3)=c^2-3c+2c-6=c^2-c-6
б) (2a-1)(3a+4)=5a^2+8a-3a-4=5a^2+5a-4
в) (5x-2y)(4x-y)=20x^2-5xy-8xy-2y^2=20x^2-13xy-2y^2
г) (a-2)(a^2-3a+6)=a^3-3a^2+6a-2a^2+6a-12=a^2-5a^2+12a-12
2. а) a(a+3)-2(a+3)=(a-2)(a+3)
б) ax-ay+5x-5y=a(x-y)+5(x-y)=(a+5)(x-y)
3. а) (2a^2-3a+1)-(7a^2-5a)=2a^2-3a+1-7a^2+5a=-5a^2+2a+1
б) 3x(4x^2-x)=12x^3-3x^2
4. а) 2xy-3xy^2=xy(2-3y^2)
б) 8b^4+2b^3=2b^3(4b+1)
5. 7-4(3x-1)=5(1-2x)
7-12x+4-5+10x=0
6-2x=0
-2x=6 |:(-2)
x=-3
6. 2a^2+2ab-2ac-2ab+2b^2+2bc+2ac-2bc+2c^2=2a^2+2b^2+2c^2