[tex]\frac{4}{x} =\frac{5}{10}[/tex] [4 over x equals 5 over 10]
Solve for x, so you need to isolate/get x by itself in the equation.
[tex]\frac{4}{x} =\frac{5}{10}[/tex] Multiply x on both sides
[tex](x)\frac{4}{x}=\frac{5}{10} (x)[/tex]
[tex]4=\frac{5}{10} x[/tex] Multiply the inverse of 5/10, which is 10/5, to get rid of the fraction and get x by itself
[tex](\frac{10}{5} )4=(\frac{10}{5} )\frac{5}{10} x[/tex]
[tex]\frac{40}{5} =x[/tex]
8 = x