First, we apply the distributive property of multiplication:
[tex]\begin{gathered} 5x+5\cdot20=7x+30, \\ 5x+100=7x+30. \end{gathered}[/tex]Subtracting 5x from the above equation we get:
[tex]\begin{gathered} 5x+100-5x=7x+30-5x, \\ 100=2x+30. \end{gathered}[/tex]Now, subtracting 30 we get:
[tex]\begin{gathered} 100-30=2x+30-30, \\ 70=2x\text{.} \end{gathered}[/tex]Finally, dividing by 2 we get:
[tex]\begin{gathered} \frac{2x}{2}=\frac{70}{2}, \\ x=35. \end{gathered}[/tex]Answer: x=35.
