Answer: x = 9
Explanation: In this problem, we're given a triangle and information
about each of its angles and we're asked to find the value of x.
The measures of the angle of a triangle always add to 180 degrees.
So we can setup the equation 6x + 1 + 9x + 4 + 6x - 14 = 180.
Simplifying on the left side, we have 21x - 9 = 180.
Adding 9 to both sides, we have 21x = 189.
Now divide both sides by 21 to get x = 9.
