For supplementary angles, we can do the following equality
[tex]3x+4=x+70[/tex]What we have to do, is to clear "x" to find its value.
[tex]\begin{gathered} 3x-x=70-4 \\ 2x=66 \\ x=\frac{66}{2} \\ x=33 \end{gathered}[/tex]In conclusion, the value of x is 33
