Answer:
x = 18
Explanation:
1. Let's solve for x, using the supplementary angles theorem, this way:
∠ C = 180 - 7x + 2 because they are supplementary angles. And these angles add up to 180 degrees.
∠ D = 180 - 9x + 31 because they are supplementary angles. And these angles add up to 180 degrees.
∠ E = 180 - 4x - 33 because they are supplementary angles. And these angles add up to 180 degrees.
Now, let's recall that the interior angles of a triangle add up to 180 degrees. Thus:
∠ C + ∠ D + ∠ E = 180 °
Replacing with the real values for solving for x:
180 - 9x + 31 + 180 - 4x - 33 + 180 - 7x + 2 = 180
- 20 x + 540 = 180
- 20 x = 180 - 540 (Subtracting 540 to both sides)
- 20 x = - 360
x = 18 (Dividing by - 20)
Proving that x = 18 is correct
180 - 9x + 31 + 180 - 4x - 33 + 180 - 7x + 2 = 180
180 - 9 (18) + 31 + 180 - 4 (18) - 33 + 180 - 7 (18) + 2 = 180
180 - 162 + 31 + 180 - 72 - 33 + 180 - 126 + 2 = 180
573 - 393 = 180
180 = 180
We proved that x = 18 is correct