(X-1/2)²－9/4=0
X-1/2=±3/2
X1=2
X2=-1
（x²-x）²-1分之x²-x+2的值等于4/3
又：x²-x-2=0
则x²-x=2
（x²-x）²-1分之x²-x+2的值等于3分之4