1.

1)5а(а4-6а^2+3)=5а^5-30а^3+15а.

2)(х+4)(3х-2)=3х^2-

2х+12х-8=3х^2+10х-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^56x^2-x-30.