Answer:
The sum of the two interior angles of the triangle are equal to the exterior angle.
So we set up the equation;
(3x + 8) + x = 6x - 32
Combine like terms:
4x + 8 = 6x - 32
Let's get rid of the constants on the right side by adding 32 to both sides (because we're applying inverse operations)
+32 +32
4x + 40 = 6x
Now let's group the coefficients that have x, by subtracting 4x from both sides;
-4x -4x
40 = 2x
Divide by 2 so we can isolate x;
/2 /2
20° = x