Answer:
m∠6 = 116°
Step-by-step explanation:
first find x:
7x - 17 = 2x + 78
subtract 2x from both sides: 5x - 17 = 78
add 17 to both sides: 5x = 95
divide by 5: x = 19
plug x into 7x - 17
7(19) - 17 = 116
∠6 and 7x - 17 are vertical angles and therefore congruent, so m∠6 also = 116°
