The answer is 201.
The total sum of all angle in a triangle is 180°. All of the angles are same in this equilateral triangle. [tex] \frac{1}{3}x-7 [/tex] added three times, or multiplied by 3 equals 180°. [tex] 3(\frac{1}{3}-7)=180 [/tex] Then you solve to get the value of x!
[tex] x-21=180 [/tex]
[tex] x-21+21=180+21 [/tex]
[tex] x=201 [/tex]
Now you have the value of [tex] x [/tex]!
[tex] x=201 [/tex]
