Answer:
x = -9
Explanation:
Notes to remember:
A triangle's angles will always add up to 180°
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As the image shows, we have two labeled angles. A 51° angle and a 65° angle.
Here's how you want to set up your equation:
180° = 51 + 65 + x + 73
(Rearrange)
180° = 51 + 65 + 73 + x
Add 51, 65, and 73
180° = 189 + x
Subtract 189 from both sides, to isolate x.
-9° = x
ALWAYS PLUG IN (the number that comes from the variable) TO CHECK YOUR WORK!
180° = 51 + 65 - 9 + 73
I hope this helped!
Sincerely,
Your friendly neighborhood
Middle School Math Teacher