Answer:
a = 10
Explanation:
The image is showing a linear pair which equals 180°
104° is shown.
If you take 180° and subtract 104° you should get the answer to what (8a -4)° should equal to.
180° - 104° = 76°
Your equation should look like : 8a - 4 = 76°
-- Add 4 to both sides
8a - 4 = 76°
+4 +4
= 8a = 80
-- Divide 8 on both sides
8a/8 = 80/8
a = 10
Proof:
8(10) - 4 =
80 - 4 = 76°
104° + 76° = 180°
Hope this helps!
--Blu