Answer:
x=3
Step-by-step explanation:
We have to use the fact that all angles of a triangle add up to 180 and two supplementary angles add up to 180.
First,QRS forms a line, so angle QRT and angle TRS add up to 180 or, if we call angle TRS y for the sake of having it as a variable, 45x+y=180 or y=180-45x
Now we have all three angles of the triangle, and we know all three add up to 180, so startign with our newly found angle, (180-45x)+(25x)+(57+x)=180
180-45x+25x+57+x=180
237 - 19x = 180
57 = 19x
x=3
Let me know if you need any further explanation.
