Answer:
x = 31°
Step-by-step explanation:
All the angles given, a, 2x, and 3x, form a straight lines, so therefore, they add up to 180°. We can write an equation from the info:
a + 2x + 3x = 180°
We know a is 25°, so we can substitute that in:
25° + 2x + 3x = 180°
Combine like terms...
25° + 5x = 180°
And solve.
5x = 155°
x = 31°
