Factor polynomial $$ -81x^{2}+121 $$
Answer
$$ -81x^{2}+121 = ( -9x+11 )( 9x+11 ) $$
Explanation
Rewrite $ -81x^{2}+121 $ as:
$$ -81x^{2}+121 = 121 -81x^2 = (11)^2 - (9x)^2 $$Now we can apply the difference of squares formula.
$$ I^2 - II^2 = (I - II)(I + II) $$After putting $ I = 11 $ and $ II = 9x $ , we have:
$$ -81x^{2}+121 = (11)^2 - (9x)^2 = ( -9x+11 ) ( 9x+11 ) $$This page was created using
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