Question

What is 3f (x) · g(x) if f(x) = 2x andg(x) = 5x? -7?A30x2 – 14xB. 10x’ – 14xC. 30x3 – 42xD.30x² – 21x

Answer 1

Given:

`\begin{gathered} f(x)=2x \\ g(x)=5x^2-7 \end{gathered}`

Now, 3f(x)· g(x) can be expressed as,

`\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}`

Therefore, 3f(x)· g(x) is,

`30x^3-42x`

Hence, option C is correct.