Question 34737
Well, a good place to begin is remembering that the sum of the interior angles of any plane triangle is always 180 degrees. Applying this to your problem:

a = (42-x) degrees, b = (9x-32) degrees, and, although you don't say it, assume that c = x degrees, so, a+b+c = 180:
(42-x) + (9x-32) + x = 180 Simplify and solve for x.
9x + 10 = 180 Subtract 10 from both sides.
9x = 170 Divide both sides by 9.
x = 170/9
x = 18.9 degrees.
42-x = 42-18.9 = 23.1
9x-32 = 9(18.9)-32 = 138.1

The three angles are:
a = 23.1 degrees
b = 138.1 degrees
c = 18.9 degrees

You have your notation a bit mixed up when you ask to find the unknown angles, a, b, and c. The at the end you say..."Please find A, B, and C"  Usualyy, the capital letters are used to denote the sides of a triangle. Do you need to find the lengths of the sides also?  You cannot find the lengths of the sides by just knowing the three angles.  Why, because you can have any number of similar triangles with these three angles but all having different side lengths.