Question

Factorise by using formula:

${\left(7\frac{3}{10}\right)}^2-{\left(2\frac{1}{10}\right)}^2$ is $48\frac{22}{25}$
If true then enter $1$ and if false then enter $0$.

Answer 1

Formula $a^2-b^2=(a+b)(a-b)$
Applying the formula, we get
${\left(7\frac{3}{10}\right)}^2-{\left(2\frac{1}{10}\right)}^2=(7\frac{3}{10}+2\frac{1}{10})(7\frac{3}{10}-2\frac{1}{10})=(\frac{73}{10}+\frac{21}{10})(\frac{73}{10}-\frac{21}{10})=\frac{94}{10}\times \frac{52}{10}=\frac{1222}{25}=48\frac{22}{25}$