解
1/4-(-4x²+2x-8)-1/2(x-2)
=1/4+4x²-2x+8-1/2x+1
=4x²-5/2x+37/4
=4×(1/4)-5/2×(1/2)+37/4
=1-5/4+37/4
=1+8
=9
6y+4y²-9=7
∴6y+4y²=16
∴3y+2y²=8
∴2y²+2y+7
=8+7
=15说错了= =是四分之一(-4x²+2x-8)-二分之一(x-2)其中x=二分之一==解1/4(-4x²+2x-8)-1/2(x-2)=-x²+1/2x-2-1/2x+1=-x²-1=-(1/2)²-1=-1/4-1=-5/4