48 degrees and the 5x-17 are alternative interior angles meaning they’re equal so you set the equation up as 5x-17=48, you then add the 17 to the 48 clearing it from the left side of the equation and you get 5x=65 you then divide the 65 by 5 and you get 13 which means x=13. To solve for Y you need to realize that Y+48 MUST equal 180 because they are supplementary angles so you solve by subtracting 48 from 180 and you end up with Y=132 DEGREES don’t forget to add you label. Hope that helped.
This is just a math equation. Just add 12 1/2 to 1 2/5 and remember that the bottoms of fractions have to be the same and if you change the bottoms, you have to change the top just as much :)