#### Answer

$x=-\dfrac{3k+1}{5k+2}$

#### Work Step by Step

$-x=(5x+3)(3k+1)$
Evaluate the product on the right side:
$-x=15kx+5x+9k+3$
Take all terms with $x$ to the left side:
$-x-15kx-5x=9k+3$
Simplify the left side:
$-6x-15kx=9k+3$
Take out common factor $x$ from the left side:
$x(-6-15k)=9k+3$
Take $-6-15k$ to divide the right side:
$x=\dfrac{9k+3}{-6-15k}$
Simplify the right side:
$x=-\dfrac{3(3k+1)}{3(5k+2)}$
$x=-\dfrac{3k+1}{5k+2}$