3x^2-[7x-(4x-2)-2x^2]计算

问题描述:

3x^2-[7x-(4x-2)-2x^2]计算

3x^2-[7x-(4x-2)-2x^2]
=3x^2-[7x-4x+2-2x^2]
=3x^2-[3x+2-2x^2]
=3x^2-3x-2+2x^2
=3x^2+2x^2-3x-2
=5x^2-3x-2(-x^2++4x)+(5x-4+2x^2)化简(-x^2+4x)+(5x-4+2x^2)=-x^2+4x+5x-4+2x^2=2x^2-x^2+4x+5x-4=x^2+9x-4是(-x^2+5+4x)+(5x-4+2x^2)化简(-x^2+5+4x)+(5x-4+2x^2)=-x^2+5+4x+5x-4+2x^2=2x^2-x^2+4x+5x+5-4=x^2+9x+1