2)* Упрости выражения: a) 19 + 8x + 32 +21х; б) а+78а; в) 4⋅y⋅5⋅z⋅10; г) 8c-2c-5c.

a) 19 + 8x + 32 + 21x = (19 + 32) + (8x + 21x) = 51 + 29x

б) a + 78a = 1a + 78a = (1 + 78)a = 79a

в) 4 ⋅ y ⋅ 5 ⋅ z ⋅ 10 = (4 ⋅ 5 ⋅ 10) ⋅ y ⋅ z = 200yz

г) 8c - 2c - 5c = (8 - 2 - 5)c = 1c = c