Answer :
[tex](f+g)(x)=3x-1+7x=10x-1\\
(f+g)(6)=10\cdot6-1=59\\\\
(f-g)(x)=3x-1-7x=-4x-1\\
(f-g)(x)=-4\cdot(-3)-1=11\\\\
(f\cdot g)(x)=(3x-1)\cdot7x=21x^2-7x\\
(f\cdot g)(x)=21\cdot5^2-7\cdot5=525-35=490\\\\
\left( \dfrac{f}{g}\right)(x)=\dfrac{3x-1}{7x}\\
7x\not=0 \Rightarrow x\not=0 \Rightarrow \left( \dfrac{f}{g}\right)(0) \text{ doesn't exist}
[/tex]
