Question

Nếu \(g\left(x\right)=\left(2x+1\right)^2\) và \(f\left(x\right)=2x-1\) thì \(f\left(g\left(3\right)\right)\)=

Answer 1

Giải:

Ta có: \(g\left(x\right)=\left(2x+1\right)^2\)

\(\Leftrightarrow g\left(3\right)=\left(2.3+1\right)^2\)

\(\Leftrightarrow g\left(3\right)=\left(6+1\right)^2\)

\(\Leftrightarrow g\left(3\right)=7^2=49\)

Ta có:

\(f\left(x\right)=2x-1\)

\(\Leftrightarrow f\left(g\left(3\right)\right)=2.49-1\)

\(\Leftrightarrow f\left(g\left(3\right)\right)=97\)

Vậy ...

Answer 2

f(g(x))=2.(2x+1)^2-1

f(g(3))=2.(2.3+1)^2-1=97