Question

how to solve it
$x ^{4} + 4$

Answer 1

${( {x}^{2} )}^{2} + {( {2}^{2}) }^{2} \\ { ({x}^{2} +2) }^{2} = {x}^{4} + 4 + 2{x}^{2} .2 \: \\ so \\ {x}^{4} + 4 = { ({x}^{2} + 2) }^{2} - 4{x}^{2}$
hope this will help you.