Answer
$x = 53$
Work Step by Step
If $a | | b$, then alternate interior angles are equal.
Let us set the two alternate interior angles equal to one another:
$2x + 18 = 124$
Subtract $18$ from each side of the equation to isolate the $x$ term to one side of the equation and the constants on the other:
$2x = 124 - 18$
$2x = 106$
Divide each side by $2$ to solve for $x$:
$x = 53$
