Answer:
[tex]x=9[/tex]
Step-by-step explanation:
For this you just have to make an equation and in order to do that you have to know that all these angles will equal 180°. Now we can write it out.
[tex]3x-4+13x+2+5x-7=180[/tex]
Now we combine like terms:
[tex]21x-9=180[/tex]
Add the 9 on both sides:
[tex]21x=189[/tex]
Divide the 21 on both sides:
[tex]x=9[/tex]
