解
√x³+4x²+x+25
=√x³+4x²+4x-3x-6+31
=√x(x²+4x+4)-3(x+2)+31
=√(√3-2)(x+2)²-3(x+2)+31
=√(√3-2)(√3-2+2)²-3(√3-2+2)+31
=√3(√3-2)-3√3+31
=√3√3-6-3√3+31
=√25
=5