For what value of x will the line l and m be parallel to each other?
Question:

For what value of x will the line l and m be parallel to each other?

Solution:

For the lines l and m to be parallel

$\Leftrightarrow 3 x-20=2 x+10 \quad$ [Corresponding Angles]

$\Leftrightarrow x=\mathbf{3 0}$