Recall that all three angles in a triangle equals 180.
Knowing this, we just have to add up all the angles and figure out what the value 'x' is.
(x-22 + x-17 + 3x+19) = 180
Simplify:
5x - 20 = 180
Add 20 to both sides:
5x = 200
Divide both sides by 5:
x = 40
Now that we found the value for x, we need to solve for angle A.
Simply input the value of 'x' into angle A's equation:
40 - 22 = 18
Angle A = 18 degrees
Good luck! If you need me to explain anything, just ask :))
-T.B.