№ 2 Группировка: 1) ax + bx + ac + bc 2) 4a + by + ay + 4b 3) px + py - 5x – 5y 4) 3a - 3c + xa - xc 5) 6x + 7y + 42 + xy 6) ab - ac 4b + 4c

Ответ:

1. ax + bx + ac + bc = x(a + b) + c(a + b) = (a + b)(x + c)
2. 4a + by + ay + 4b = 4a + ay + 4b + by = a(4 + y) + b(4 + y) = (4 + y)(a + b)
3. px + py - 5x – 5y = p(x + y) - 5(x + y) = (x + y)(p - 5)
4. 3a - 3c + xa - xc = 3(a - c) + x(a - c) = (a - c)(3 + x)
5. 6x + 7y + 42 + xy = 6x + 42 + 7y + xy = 6(x + 7) + y(7 + x) = (x + 7)(6 + y)
6. ab - ac - 4b + 4c = a(b - c) - 4(b - c) = (b - c)(a - 4)