Answer:
- equation: (4x +8)° = (2x +3)° +51°
- exterior angle: 100°
Explanation:
The relevant relation is "the exterior angle is equal to the sum of the remote interior angles." That means ...
(4x +8)° = (2x +3)° +51° . . . equation to solve for x
2x = 46 . . . . . . . . . . . . . divide by °, subtract 8+2x
x = 23 . . . . . . . . . . . . divide by 2
Then the exterior angle is ...
(4x +8)° = (4(23) +8)° = 100°
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Additional comment
Instead of solving for x, we can solve for (2x+3). We can do that by subtracting 5+2x from both sides to get 2x+3 = 49. Then the exterior angle is the sum 49+51 = 100 degrees. (We don't actually care about the value of x.)