Question

\(21.7^2-11.7^2+90.7^2+49.125.16\)

Answer 1

\(21\cdot7^2-11\cdot7^2+90\cdot7^2+7^2\cdot125\cdot16\)

\(=7^2\left(21-11+90+2000\right)\)

\(=7^2\cdot2100\)

\(=102900\)

Answer 2

= 7 mũ 2 . ( 21 - 11 + 90 ) + 49.125.16

= 7 mũ 2 . 100 + 49.125.16

= 4900 + 49.125.16

= 4900 + 98000

= 102900