Answer:
No, he should have set the sum of ∠AED and ∠DEC equal to 180°, rather then setting ∠AED and ∠DEC equal to each other
Explanation:
Find the diagram attached
If line AC and BD intersects, then m<AED + m<DEC = 180 (sum of angle on a straight line is 180 degrees)
Given
m<AED = 16x+8
m<DEC = 76 degrees
16x + 8 + 76 = 180
16x + 84 = 180
16x = 180-84
16x = 96
x = 96/16
x = 6
Hence the value of x is 6
Hence the correct option is No, he should have set the sum of ∠AED and ∠DEC equal to 180°, rather then setting ∠AED and ∠DEC equal to each other