Not exactly sure but I think it's 74.2
Both of this angles are same side interior angles which means both of this angles when added equal to 180 degrees
5x +15 + 3x - 3 = 180
8x - 12 = 180
+12 +12
8x = 192
x = 24
Yes, that is true, you have to simplify -42/-45 to be able to see if they are equivalant.