In this case, to find the solution to the exercise we'll have to carry out several steps.
Step 01:
The sum of the two angles is equal to 180 degrees
(2x - 18) + (5x -19) = 180
Step 02:
Solve the equation
2x + 5x = 180 + 18 + 19
7 x = 217
x = 217 / 7 = 31
The answer is:
X = 31 °