若x^2+3x-2=0,则x^3+5x^2+4x+18等于

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若x^2+3x-2=0,则x^3+5x^2+4x+18等于

若x^2+3x-2=0,则x^3+5x^2+4x+18等于
若x^2+3x-2=0,则x^3+5x^2+4x+18等于

若x^2+3x-2=0,则x^3+5x^2+4x+18等于
x^2+3x-2=0
x^2+3x=2
x^3+5x^2+4x+18
=x^3+3x^2+2x^2+4x+18
=x(x^2+3x)+2x^2+4x+18
=2x+2x^2+4x+18
=2x^2+6x+18
=2(x^2+3x)+18
=2*2+18
=4+18
=22

x^3+5x^2+4x+18
=x(x^2+3x-2)+2x^2+6x-4+22
=22