Question

If $f\left(x\right)=\frac{3x+5}{2x-3}$, then $f\left(15\right)+f(-10)=$

• A. $\frac{1855}{629}$
• B. $\frac{1875}{621}$
• C. $\frac{1825}{621}$
• D. $\frac{1875}{629}$

Answer 1

Answer: (C)

$\frac{1825}{621}$

We have,

$f\left(x\right)=\frac{3x+5}{2x-3}$ $............\left(1\right)$

Put $x=15$

$f\left(15\right)=\frac{3\times 15+5}{2\times 15-3}$

$f\left(15\right)=\frac{45+5}{30-3}$

$f\left(15\right)=\frac{50}{27}$

Put $x=-10$

$f(-10)=\frac{3\times -10+5}{2\times -10-3}$

$f(-10)=\frac{-30+5}{-20-3}$

$f(-10)=\frac{-25}{-23}$

$f(-10)=\frac{25}{23}$

Since,

$f\left(15\right)+f(-10)$

$\Rightarrow \frac{50}{27}+\frac{25}{23}$

$\Rightarrow \frac{1150+675}{621}$

$\Rightarrow \frac{1825}{621}$

Hence, this is the answer.