8x^2-[-3x-(2X^2-7x-5)+3]+4x.

问题描述:

8x^2-[-3x-(2X^2-7x-5)+3]+4x.

=8x^2-[-3x-2x^2+7x+5+3]+4x
=8x^2+3x+2x^2-7x-5-3+4x
=10x^2-8