[tex] {( \sqrt{7} - \sqrt{5} ) }^{2} = {( \sqrt{7}) }^{2} - 2 \times \sqrt{7} \times \sqrt{5} + {( \sqrt{5} )}^{2} [/tex]
[tex] = 7 - 2 \sqrt{7 \times 5} + 5[/tex]
[tex] = 7 - 2 \sqrt{35} + 5[/tex]
[tex] = 12 - 2 \sqrt{35} [/tex]
[tex] = 2(6 - \sqrt{35} )[/tex]
[tex]Formul\check{a}\::{(a-b)}^{2}={a}^{2}-2ab+{b}^{2}[/tex]
