Question

Factorise:
${\left(7\frac{3}{10}\right)}^2-\left(2\frac{1}{10}\right)$

Answer 1

${\left(7\frac{3}{10}\right)}^2-{\left(2\frac{1}{10}\right)}^2\Rightarrow {\left(\frac{73}{10}\right)}^2-{\left(\frac{21}{10}\right)}^2$

$\Rightarrow (\frac{73}{10}-\frac{21}{10})(\frac{73}{10}+\frac{21}{10})$

$\Rightarrow \left(\frac{51}{10}\right)\left(\frac{94}{10}\right)\Rightarrow \left(5\frac{2}{10}\right)\left(9\frac{4}{10}\right)$