Question

please tell very urgent , only 7th question

Answer 1

$\boxed{\boxed{\boxed{\bold{\blue{Solution :\longrightarrow}}}}}$

$\bold{By \: \: using \: \: the \: \: formula \: \: of}$

$\bold\red{\underline{( {a - b)}^{2} = {a}^{2} - 2ab + {b}^{2} ,\: \: we \: \: get}}$

$\bold{= (6 {x}^{2} {y}^{3} ) {}^{2} - 2.6 {x}^{2} {y}^{3} . \frac{1}{3} x {y}^{3} + ( \frac{1}{3} x {y}^{3} ) {}^{2}} \\ \\ \bold{= 36 {x}^{4} {y}^{6} - 4 {x}^{3} y {}^{9} + \frac{1}{9} {x}^{2} {y}^{6}} \\ \\ \bold{= 36 {x}^{4} {y}^{6} + \frac{1}{9} {x}^{2} {y}^{6} - 4 {x}^{3} {y}^{9}}$