• # question_answer   Using a suitable identity to get the product $\left( 3x-\frac{1}{3} \right)\left( 3x-\frac{1}{3} \right)$.

Using the identity ${{\left( a-b \right)}^{2}}={{a}^{2}}-2ab+{{b}^{2}},$ We have,  $\left( 3x-\frac{1}{3} \right)\left( 3x-\frac{1}{3} \right)={{\left( 3x-\frac{1}{3} \right)}^{2}}$ $={{(3x)}^{2}}-2(3x)\left( \frac{1}{3} \right)+{{\left( \frac{1}{3} \right)}^{2}}$ $=9{{x}^{2}}-2x+\frac{1}{9}.$