857. 1) ax+ay + bx + by; 3) a² + ab + ac + bc; 858. 1) ac+bc+a+b; 3) xy+xz+y+z; 859. 1) x³ + 3x²+3x-9; 3) m²+mn-5m - 5n; 860. 1) 10ay-5by+2ax-bx; 3) 5a² - 5ax-7a+7x;

857

1. ax + ay + bx + by = a(x+y) + b(x+y) = (a+b)(x+y)
2. ax - ay + bx - by = a(x-y) + b(x-y) = (a+b)(x-y)
3. a² + ab + ac + bc = a(a+b) + c(a+b) = (a+c)(a+b)
4. x²+xy+ax+ay = x(x+y) + a(x+y) = (x+a)(x+y)

858

1. ac+bc+a+b = c(a+b) + (a+b) = (c+1)(a+b)
2. am+an+m+n = a(m+n) + (m+n) = (a+1)(m+n)
3. xy+xz+y+z = x(y+z) + (y+z) = (x+1)(y+z)
4. 3a - 3b+ax - bx = 3(a-b) + x(a-b) = (3+x)(a-b)

859

1. x³ + 3x²+3x-9 = x²(x+3) + 3(x-3)
2. x² - xy - 2x + 2y = x(x-y) - 2(x-y) = (x-2)(x-y)
3. m²+mn-5m - 5n = m(m+n) - 5(m+n) = (m-5)(m+n)
4. a²- ab -3a+3b = a(a-b) - 3(a-b) = (a-3)(a-b)

860

1. 10ay-5by+2ax-bx = 5y(2a-b) + x(2a-b) = (5y+x)(2a-b)
2. 6by-15bx-4ay+10ax = 3b(2y-5x) - 2a(2y-5x) = (3b-2a)(2y-5x)
3. 5a² - 5ax-7a+7x = 5a(a-x) - 7(a-x) = (5a-7)(a-x)
4. 4x² - 4xz-3x+3z = 4x(x-z) - 3(x-z) = (4x-3)(x-z)

Ответ: смотри решение выше

Ты молодец! У тебя всё получится!