1) $$5a(a^4 - 6a^2 + 3) = 5a^5 - 30a^3 + 15a$$
2) $$(x+4)(3x-2) = 3x^2 - 2x + 12x - 8 = 3x^2 + 10x - 8$$
3) $$(6m + 5n)(7m - 3n) = 42m^2 - 18mn + 35mn - 15n^2 = 42m^2 + 17mn - 15n^2$$
4) $$(x+5)(x^2+x-6) = x^3 + x^2 - 6x + 5x^2 + 5x - 30 = x^3 + 6x^2 - x - 30$$
**Ответ:**
1) $$5a^5 - 30a^3 + 15a$$
2) $$3x^2 + 10x - 8$$
3) $$42m^2 + 17mn - 15n^2$$
4) $$x^3 + 6x^2 - x - 30$$