Given the following:
Then:
[tex]a=\frac{b-c}{2}[/tex]
In this case, we are given:
a = (9x + 26)
b = 251
To find c, we rest a whole circle (360) and rest angle b:
[tex]c=360-251=109[/tex]
And now, we use the formula from above:
[tex]9x+26=\frac{251-109}{2}[/tex]
And solve for x:
[tex]\begin{gathered} 9x+26=\frac{142}{2} \\ . \\ 9x=71-26 \\ . \\ x=\frac{45}{9} \\ . \\ x=5 \end{gathered}[/tex]
The answer is the last option, x = 5
