
ա) (a + 3)7 = 7a + 21
դ)a(a + b) = a2 + ab
է)x (x – y + c) = x2 – xy + xc
գ)a(x — y)
զ) (a – b)(-6) = -6a – 6b

բ) (7 + 3y – x2y)(-2xy) = -14xy – 3xy2 – 2x3y2
դ)2a (x + y) = 2ax + 2ay
զ)21a2b5 (a3 – 4ab2 — b2) = 21a5b5 – 84a3b7 — 21a2b7
ը)-ac (a + 2c) = -a2c – 2ac2