Answer:
x = 154/13
Step-by-step explanation:
You are given the measures of all three angles in a triangle
so according to the Triangle Sum Theorem:
∠MNO + ∠OMN + ∠NOP = 180
1. Substitute the measures of the angles into the equation:
(3x + 11) + (2x + 20) + (8x - 5) = 180
2. Combine like terms:
(3x + 2x + 8x) + (11 + 20 -5) = 180
13x + 26 = 180
3. Isolate x by subtratcing 26 from both sides
13x + 26 -26 = 180 -26
13x = 154
4. Solve for x by dividing both sides by 13
13x/13 = 154/13
x = 154/13
