We are given two complementary angles (QRS and SRT).
Two angles are called complementry if they sum up to 90 degrees.
Therefore, by defination
mQRS + mSRT = 90
(8x+10) + (8x) = 90
8x + 8x + 10 = 90
16x = 90-10
16x = 80
x = 80/16
x = 5
Now, put the values in both the euqations and we will get the values of both the angles.
mQRS = 8x + 10 = 8(5) + 10 = 40 + 10 = 50 degrees
mSRT = 8x = 8(5) = 40 degrees