Question

I . factorize using the suitable Identity . a. 81 a⁴- 72a²b²+ 16b⁴​

Answer 1

$\sf {81a}^{4} - {72a}^{2} {b}^{2} + {16b}^{4} \\ \sf {( {9a}^{2} )}^{2} - 2( {9a}^{2} )( { - 4b}^{2} ) + {( {4b}^{2} )}^{2} \\ \\ \huge \sf {( {9a}^{2} - {4b}^{2} )}^{2}$