SOLUTION: ∠A and ∠B are vertical angles. If m∠A=(2x+15)∘ and m∠B=(5x−15)∘, then find the value of x.

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Question 1058603: ∠A and ∠B are vertical angles. If m∠A=(2x+15)∘ and m∠B=(5x−15)∘, then find the value of x.
Found 3 solutions by Boreal, ikleyn, Alan3354:
Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
Vertical angles are equal
2x+15=5x-15
3x=30
x=10 degrees
check
20+15=50-15
35=35
Answer by ikleyn(52797)   (Show Source): You can put this solution on YOUR website!
.
Since the angles are vertical, they are congruent.

So, their measures are the same:

2x + 15 = 5x - 15,  or

15 + 15 = 5x - 2x,  or

30 = 3x,

x =  = 10.

Answer.  x = 10 degrees.

On vertical angles see the lesson
     - Vertical angles
in this site. It is one of the basic notions of the elementary geometry.


Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
Vertical is a direction, not an angle.
There is no "vertical angle."
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