Question

3x^3一(x^3一2x^2+18x)一3/1(6x^3一6x^2十12x)

Answer 1

3x^3一(x^3一2x^2+18x)一3/1(6x^3一6x^2十12x)

=3x^3一x^3+2x^2-18x一(2x^3一2x^2十4x)

=2x^3+2x^2-18x一2x^3+2x^2-4x

=（2x^3一2x^3）+（2x^2+2x^2）-（18x+4x）

=4x^2-22x