These are complementary angles, meaning they add up to 180
Let's write an equation
180=38 + 42 + (2x+10)
subtract 38 from both sides
142 = 42 + 2x + 10
subtract 42 from both sides
100 = 2x + 10
subtract 10 from both sides
90 = 2x
divide both sides by 2
45 = x
Plug that back into the angle
2x+10
2(45)+ 10
90 + 10
100
The angle is 100 degrees.
To check:
180 =?= 38 + 42 + (2x+10)
180 =?= 38 + 42 + (2(45) + 10)
180 =?= 80 + (90 + 10)
180 =?= 80 + 100
180 = 180
Hope this helps :)