Given:
[tex]\begin{gathered} f(x)=2x \\ g(x)=5x^2-7 \end{gathered}[/tex]
Now, 3f(x)· g(x) can be expressed as,
[tex]\begin{gathered} 3f\mleft(x\mright)\cdot g\mleft(x\mright)=3\cdot2x\cdot(5x^2-7) \\ =6x\cdot(5x^2-7) \\ =6x\cdot5x^2+6x\cdot(-7) \\ =30x^3-42x \end{gathered}[/tex]
Therefore, 3f(x)· g(x) is,
[tex]30x^3-42x[/tex]
Hence, option C is correct.
