Answer: 11
Step-by-step explanation:
We are given that ∠E and ∠F are vertical angles with m∠E=5x+10 and m∠F=7x−12 .
We know that vertical angles are congruent, then their measures must be equal.
i.e. if ∠E and ∠F are vertical angles.
⇒ m∠E=m∠F
[Substitute the measures of ∠E and ∠F]
Subtract 5x from both sides , we get
Add 12 on both sides , we get
Divide both sides by 2 , we get
or x=11
Hence, the value of x= 11