Since those are consecutive interior angles, we can conclude:
[tex]\begin{gathered} 4x+6x=180 \\ _{\text{ }}add_{\text{ }}like_{\text{ }}terms\colon \\ 10x=180 \\ _{\text{ }}solve_{\text{ }}for_{\text{ }}x\colon \\ \frac{10x}{10}=\frac{180}{10} \\ x=18 \end{gathered}[/tex]
Answer:
18
