x = 6
given [tex]\frac{3}{x}[/tex] + [tex]\frac{1}{3}[/tex] = [tex]\frac{5}{6}[/tex]
to eliminate the fractions multiply through by the lowest common multiple of x, 3 and 6 , that is 6x
multiply all terms by 6x gives
18 + 2x = 5x ( subtract 2x from both sides )
18 = 3x ( divide both sides by 3 )
6 = x
As a check
[tex]\frac{3}{6}[/tex] + [tex]\frac{1}{3}[/tex] = [tex]\frac{3}{6}[/tex] + [tex]\frac{2}{6}[/tex] = [tex]\frac{5}{6}[/tex]