Can someone explain how to get the answer, (105)/(2) ? I'm confused

Question

Can someone explain how to get the answer,

`(105)/(2)`
? I'm confused

Answer 1

First eliminate the fractions by multiplying each term by 35:-

7x - 5x = 105

2x = 105

x = 105/2

Answer 2

`\bf \cfrac{x}{5}-\cfrac{x}{7}=3\impliedby \begin{array}{llll} \textit{let's multiply both sides by }\stackrel{LCD}{35}\\ \textit{to do away with the denominators} \end{array} \\\\\\ 35\left( \cfrac{x}{5}-\cfrac{x}{7}\right)=35(3)\implies 7x-5x=105 \\\\\\ 2x=105\implies x=\cfrac{105}{2}`