№1
1. 5а(а^4 - 6а^3 + 3) = 5a^5 - 30a^4 + 15a
2) (x + 4)(3x - 2)= 3x^2 -2x + 12x - 8 = 3x^2 + 10x - 8
3) (6m + 5n) (7m - 3n) = 42m^2 - 18mn + 35mn - 15n = 42m^2 + 17mn - 15n
4) (x + 5)(x^2 +x - 6) = x^3 + x^2 - 6x + 5x^2 + 5x - 30 = x^3 + 6x^2 - x - 30
№2
1) 18xy - 6x^2 = 6[(3y - x2)
2) 15a^6 - 3a^4 = 3a(5a^5 - a^3)
3) 4x - 4y + cx - cy = 4(x - y) + c(x - y)
№ 4
7b(2b + 3) - (b + 6)(b - 5) = 14b^2 + 21b - b^2 - 5b + 6b-30 = 13b^2+22b-30