45x+angle trs = 180 straight line
angle trs = 180-45x
angle trs + angle t + angle tsr = 180 (sum of angles in a triangle =180)
(180-45x) + 25x + 57+x = 180
combine like terms
180 +57 -45x+25x+x=180
237-19x=180
subtract 237 from each side
-19x =-57
divide by -19
x=3
