Question

-90a+9(a+5)^2 при а=√12

Answer 1

По формуле $(a+b) ^{2} =a ^{2}+2ab+b ^{2}$
получается:
$-90\sqrt{12}+9( \sqrt{12} +5) ^{2} \\ -90\sqrt{12}+9( \sqrt{12} ^{2} +2\sqrt{12}*5+5 ^{2} ) \\ -90\sqrt{12}+9( 12 + 10\sqrt{12}+25 ) \\ -90\sqrt{12}+333 + 90\sqrt{12} \\ =333$