Answer: He should have used the mean to determine the average because the data sets are approximately symmetric.
Step-by-step explanation
I'll go by boxes (top statement box is #1, top reason box is #2, etc.)
If you don't have enough boxes, you can omit (remove) the first 2 I wrote, which is the given
1. 8y = 9x - 14; y = 5
2. Given
3. 8(5) = 9x - 14
4. Substitution
5. 40 = 9x - 14
6. Simplification (or multiplication)
7. 54 = 9x
8. Additive property of equality
9. 6 = x
10. Division property of equality
11. x = 6
12. Symmetrical property of equality
Hope this helps (:
<span>m∠3 = 180 -(x + x - 6 )
= 180 - 2x + 6
= 186 - 2x</span>
