Our goal is to get y by itself
We will first add 3x to both sides to get
-5y = 3x - 15
We will then divide both sides by -5 to get y by itself which becomes
y = -3/5x + 3
B= 60
To find b you must do the pythagorean theorem because it is a right triangle
65^2 - 25^2=b^2
3600=b^2
60=b
x= 18
To find x you must know that a triangle is made up of 180 degrees.
x= 180-(72+90)
x=180-162
x=18
hope this helped :)