Answer:
∠E = 77°
Step-by-step explanation:
You set the angles equal to each other:
9x - 5 = 8x + 4
x = 9
You also know that all angles in a triangle add up to 180°, so:
3x + (9x - 5) + ∠E = 180
3(9) + (9(9) - 5) + ∠E = 180
27 + 76 + ∠E = 180
∠E = 180 - 76 - 27
∠E = 77°
