To find the measure of y, we use the fact that 48 and y are consecutive interior angles. Since the lines that are cut by the transversal are parallel, by the Consecutive Interior Angles Theorem, we know they are supplementary. This means they add up to 180.
48 + y=180 ⇔ y=132
We see that y and (5x-17) form a linear pair. Therefore, by the Linear Pair Postulate, we know that these angles are supplementary.
(5x-17)+ y=180
By substituting the value for y, we can solve for x.
