3х(5 + х)² – х(3х – 6)²=3х(25+10х+х²)-х(9х²-36х+36)=
=75х+30х²+3х³-9х³+36х²-36х= -6х³+66х²+39х
3x(25 + 10x + x^2) - x( 9x^2 - 36x + 36) = 75x + 30x^2 + 3x^3 - 9x^3 + 36x^2 - 36x = - 6x^3 + 66x^2 +39x
3х(5 + х)² – х(3х – 6)²=3х(25+10х+х²)-х(9х²-36х+36)=
=75х+30х²+3х³-9х³+36х²-36х= -6х³+66х²+39х
3x(25 + 10x + x^2) - x( 9x^2 - 36x + 36) = 75x + 30x^2 + 3x^3 - 9x^3 + 36x^2 - 36x = - 6x^3 + 66x^2 +39x