Вправи: 626

626. Розклади на множники многочлен.

a) 4ab + 12b – 4a – 12 = 4(ab + 3b – a – 3) = 4(b • (a + 3) – (a + 3) = 4(a + 3)(b – 1);

б) 10y² – 6xy² – 5y + 3xy = y(10y – 6xy – 5 + 3x) = y(10y – 5 – (6xy – 3x)) = y(5(2y – 1) – 3x(2y – 1)) = y(2y – 1)(5 – 3x);

в) n²a + n²b – 4a – 4b = (n²a + n²b) – (4a + 4b) = n²(a + b) – 4(a + b) = (a + b)(n² – 4) = (a + b)(n – 2)(n + 2);

г) 9a – 9 – c²a + c² = (9a – 9) – (c²a – c²) = 9(a – 1) – c²(a – 1) = (a – 1) (9 – c²) = (a – 1)(3 – c)(3 + c).