Question

   KO CẦN LÀM 2 CÂU a,b phía trên

Answer 1

a: \(468^2-412^2-110\cdot412-55^2\)

\(=468^2-412^2-2\cdot412\cdot55-55^2\)

\(=468^2-\left(412+55\right)^2\)

\(=468^2-467^2\)

\(=\left(468-467\right)\left(468+467\right)\)

\(=1\cdot935=935\)

b: \(615^2+250\cdot615+125^2-540^2\)

\(=615^2+2\cdot615\cdot125+125^2-540^2\)

\(=\left(615+125\right)^2-540^2\)

\(=740^2-540^2\)

\(=\left(740-540\right)\left(740+540\right)\)

\(=200\cdot1280=256000\)