f(1/2) =3.(1/2)^2 +1=7/4
f(1)= 3.1+1=4
f(3)=3.9+1=28
Ta có: \(f\left(\frac{1}{2}\right)=3.\frac{1}{2}^2+1=\frac{7}{4}\)
\(f\left(1\right)=3\cdot1^2+1=4\)
\(f\left(3\right)=3\cdot3^2+1=28\)
Học tốt
\(y=f\left(\frac{1}{2}\right)=3.\left(\frac{1}{2}\right)^2+1=\frac{3}{4}+1=\frac{7}{4}\)
\(y=f\left(1\right)=3.1^2+1=3+1=4\)
\(y=f\left(3\right)=3.3^2+1=27+1=28\)