解
x^2+3x-3=0
x^2+3x=3
∴
x^3+5x^2+3x-10
=x(x^2+3x)+2x^2+3x-10
=3x+2x^2+3x-10
=2x^2+6x-10
=2(x^2+3x)-10
=2×3-10
=6-10
=-4