利用(根号3+根号2)乘以(根号3-根号2)=1来化简
X的6次方+2倍根号2乘以X的5次方-X的4次方+X的3次方-2倍根号3乘以X的2次方+2X+根号2
= (X的6次方+2倍根号2乘以X的5次方-X的4次方)+(X的3次方-2倍根号3乘以X的2次方+2X+根号2)
=[ (X +2倍根号2)乘以X的5次方-X的4次方]+[(X -2倍根号3)乘以X的2次方+2X+根号2]
=[ (根号3+根号2)乘以X的5次方-X的4次方]+[-(根号3+根号2)乘以X的2次方+2X+根号2]
=[(根号3+根号2)乘以X乘以X的4次方-X的4次方]+ [-(根号3+根号2)乘以X乘以X+2X+根号2]
=[(根号3+根号2)乘以(根号3-根号2)乘以X的4次方-X的4次方]+ [-(根号3+根号2)乘以(根号3-根号2)乘以X+2X+根号2]
=（X的4次方-X的4次方）+（-X+2X+根号2）
=0+（X+根号2）
=根号3