Question

cho hàm số y=f(x)=3x^3-2x^2+5.tính f(2);f(1);f(-3)

Answer 1

\(f\left(2\right)=3\cdot2^3-2\cdot2^2+5=21\)

\(f\left(1\right)=3\cdot1^3-2\cdot1^2+5=3-2+5=6\)

\(f\left(-3\right)=3\cdot\left(-3\right)^3-2\cdot\left(-3\right)^2+5=3\cdot\left(-27\right)-2\cdot9+5=-94\)

Answer 2

Ta có 

\(f\left(2\right)=3.8-2.4+5=24-3=21\)

\(f\left(1\right)=3-2+5=6\)

\(f\left(-3\right)=3.\left(-27\right)-2.9+5=-81-18+5=-94\)

Answer 3

\(f\left(2\right)=3.2^3-2.2^2+5=3.8-2.4+5=24-8+5=21\\ f\left(1\right)=3.1^3-2.1^2+5=3-1+5=7\\ f\left(-3\right)=3.\left(-3\right)^3-2.\left(-3\right)^2+5=3.\left(-27\right)-2.9+5=-81-18+5=-94\)