已知f(x)=-3x^2-x 求f(-1) f(0) f(-1/2)

f(-1) = -3 - (-1) = -2
f(0) = 0
f(-1/2) = 3×(-1/2)^2 -(-1/2) = 3/4 + 1/2 = 5/4

代进去就行啦!!

f(-1)=-3(-1)^2-(-1)=-2

f(0)=-3*0^2-0=0

f(-1/2)=-3(-1/2)^2-(-1/2)=-3/4+1/2=-1/4

4，0，5/4，很简单，直接将x用括号里相应的值代入