simplify this problem

[tex] \dfrac{49 - \frac{1}{r^2} }{7 - \frac{1}{r} } [/tex]

Rewrite the fraction as division:
[tex]= (49 - \dfrac{1}{r^2}) \div (7 - \dfrac{1}{r} )[/tex]

Make them into single fraction:
[tex]= \dfrac{49r^2 - 1}{r^2} \div \dfrac{7r - 1}{r} [/tex]

Change the divide fraction into multiplication fraction:
[tex]= \dfrac{49r^2 - 1}{r^2} \times \dfrac{r}{7r - 1} [/tex]

Factorise the difference of square a² - b² = (a + b) (a - b) :
[tex]= \dfrac{(7r+ 1)(7r - 1)}{r^2} \times \dfrac{r}{7r - 1} [/tex]

Cancel the common factors:
[tex]= \dfrac{(7r+ 1)}{r}[/tex]