8x²-[-3x-(2x²-7x-5)+3]+4x怎么变号
问题描述：
8x²-[-3x-(2x²-7x-5)+3]+4x怎么变号
答
8x²-[-3x-(2x²-7x-5)+3]+4x
=8x²-[-3x-2x²+7x+5+3]+4x
=8x²-[-2x²+4x+8]+4x
=8x²+2x²-4x-8+4x
=10x²-8
答
8x²-[-3x-(2x²-7x-5)+3]+4x
=8x²-(-3x-2x²+7x+5+3)+4x
=8x²-(-2x²+4x+8)+4x
=8x²+2x²-4x-8+4x
=10x²-8