Isolate the variable $x$ on one side.

$y=2x-5$
$+5\ \ \ \ \ \ +5$
$y+5=2x$

Solve for $x$.

$\frac{y+5}{2}=x$

Follow the steps in part (a).

Follow the steps in part (a).

$m=2n+5$

Add the variable $y$ to both sides.
You are left with $-y=3x$.
Multiply to isolate a positive $y$.

$y=-3x$