Question

\(\sqrt{117,5^2-26,5^2-1440}\)

tính.

Answer 1

\(\sqrt{117,5^2-26,5^2-1440}\)

\(=\sqrt{\left(117,5+26,5\right)\left(117,5-26,5\right)-144.10}\)

\(=\sqrt{144.91-144.10}\)

\(=\sqrt{144\left(91-10\right)}=\sqrt{144.81}=\sqrt{144}.\sqrt{81}=12.9=108\)

Answer 2

\(\sqrt{117,5^2-26,5^2-1440}\)\(=\sqrt{\left(117,5-26.5\right)\left(117.5+26,5\right)-144\cdot10}\)\(=\sqrt{91\cdot144-144\cdot10}\)

\(=\sqrt{144\cdot\left(91-10\right)}\)

\(=\sqrt{144\cdot81}\)

\(=\sqrt{144}\cdot\sqrt{81}\)

\(=12\cdot9=108\)