1、先化简,再求值：x-1分之4（x²-x)+(x-2)²,其中x=√7

1、先化简,再求值：x-1分之4（x²-x)+(x-2)²,其中x=√7
1、先化简,再求值：x-1分之4（x²-x)+(x-2)²,其中x=√7

1、先化简,再求值：x-1分之4（x²-x)+(x-2)²,其中x=√7
[4(x²-x)+(x-2)²]/(x-1)
=(4x²-4x+x²-4x+4)/(x-1)
=(5x²-8x+4)/(x-1)
=[5(x-1)²+2(x-1)+1]/(x-1)
=5(x-1)+2+1/(x-1)
=5x-3+1/(x-1)
=5√7-3+1/(√7-1)
=5√7-3+(√7+1)/6
=31√7/6-17/6