x^2=2-3x求,x^3-11x+6

问题描述:

x^2=2-3x求,x^3-11x+6

x^2=2-3x
x^2+3x=2
x^3-11x+6
=x*x^2-11x+6
=x(2-3x)-11x+6
=2x-3x^2-11x+6
=-3x^2-9x+6
=-3(x^2+3x)+6
=-3*2+6
=0