Способ группировки:
1) 16ab^2 - 5b^2c - 10c^3 + 32ac2;
2) -28ac + 35c^2 - 10cx + 8ax;
3) 6mnk + 15m^2k - 14n^3k - 35mn^2;
4) -24bx - 15c^2 + 40bc + 9cx.

1) 16ab^2 - 5b^2c - 10c^3 + 32ac2=16a(b²+2c²)-5c(b²+2c²)=(b²+2c²)(16a-5c)2) -28ac + 35c^2 - 10cx + 8ax=-7c(4a-5c)+2x(4a-5c)=(4a-5c)(2x-7c)3) 6mnk + 15m^2k - 14n^3k - 35mn^2=3mk(2n+5m)-7n²(2n+5m)==(2n+5m)(3mk-7n²)4) -24bx - 15c^2 + 40bc + 9cx=-3x(8b-3c)+5c(8b-3c)=(8b-3c)(5c-3x)