[tex] {5}^{4} \div {5}^{2} + 5( {55}^{1} - x \div 5) = {5}^{3} [/tex]
[tex] {5}^{4 - 2} + 5(55 - x \div 5) = 125[/tex]
[tex] {5}^{2} + 275 - x = 125[/tex]
[tex]25 + 275 - x = 125[/tex]
[tex]300 - x = 125[/tex]
[tex] - x = 125 - 300[/tex]
[tex] - x = - 175 \: | \times ( - 1)[/tex]
[tex]x = 175[/tex]