1.
1) -5a(a⁴-6a²+3) = -5a⁵+30a³-15a.
2) (x+4)(3x-2) = 3x²-2x+12x-8 = 3x²+10x-8.
3) (6m+5n)(7m-3n) = 42m²-18mn+35mn-15n² = 42m²+17mn-15n².
4) (x+5)(x²+x-6) = x³+x²-6x+5x²+5x-30 = x³+6x²-x-30.
2.
1) 18xy-6x² = 6x(3y-x).
2) 15a⁶-3a⁴ = 3a⁴(5a²-1).
3) 4x-4y+cx-cy = 4(x-y)+c(x-y) = (x-y)(4+c).