Question

(x^2 -4) +(x^2 +4) +16 . Which Algebraic identity is used to solve this? please solve and tell. thanks

Answer 1

$using \: (a - b)(a + b) = \: {a}^{2} - {b}^{2} \\ \\ ( {x}^{2} - 4)( {x}^{2} + 4) + 16\\ = ( { {x}^{2} })^{2} - {4}^{2} \\ = {x}^{4} - 16 \\ = {x}^{4} - 16 + 16 \: (eliminate \: the \: opposites) \\ = {x}^{4}$