Question

cho hàm số y=f(x)=3x²-1 Tính f(-1) f(1) f(2) f(5/2)

Answer 1

\(f\left(-1\right)=3\cdot\left(-1\right)^2-1=2\\ f\left(1\right)=3\cdot1^2-1=2\\ f\left(2\right)=3\cdot2^2-1=11\\ f\left(\dfrac{5}{2}\right)=3\cdot\left(\dfrac{5}{2}\right)^2-1=3\cdot\dfrac{25}{4}-1=\dfrac{71}{4}\)

Answer 2

\(f\left(-1\right)=3\cdot1-1=2\)

\(f\left(1\right)=3\cdot1^2-1=2\)

\(F\left(2\right)=3\cdot2^2-1=11\)

\(f\left(\dfrac{5}{2}\right)=3\cdot\dfrac{25}{4}-1=\dfrac{71}{4}\)