SOLUTION:
We are to find the value of x in the angles of the given triangle.
3x + 5 + 4x - 15 + 2x + 10 = 180 (sum of interior angles in triangle)
3x + 4x + 2x + 5 + 10 - 15 = 180
9x + 0 = 180
9x = 180
x = 180/9
x = 20 degrees
The correct option is A ( x = 20)
