Answer
False. Change to:
For $x=\displaystyle \frac{1}{3},\quad\frac{3x+7}{3x+10}=\frac{8}{11}$
Work Step by Step
If this were true, it would be true for any x, provided it doesn't yield 0 in the denominator.
Try x=0:
$LHS=\displaystyle \frac{0+7}{0+10}=\frac{7}{10}\neq\frac{8}{11}$
so, the statement is false.
It is true only when $x=\displaystyle \frac{1}{3},$
$LHS=\displaystyle \frac{3\cdot\frac{1}{3}+7}{3\cdot\frac{1}{3}+10}=\frac{1+7}{1+10}=\frac{8}{11}$
