Question

calculați 3√7-9√7+(-6√7)-(+√7)

Answer 1

$3 \sqrt{7} - 9 \sqrt{7} - 6 \sqrt{7} - \sqrt{7} = - 13 \sqrt{7}$

Answer 2

$3 \sqrt{7} - 9 \sqrt{7} + ( - 6 \sqrt{7}) - ( + \sqrt{7}) = \\ \\ 3 \sqrt{7} - 9 \sqrt{7} - 6 \sqrt{7} - \sqrt{7} = \\ \\ 3 \sqrt{7} - 9 \sqrt{7} - 6 \sqrt{7} - 1 \sqrt{7} = \\ \\ (3 - 9 - 6 - 1) \sqrt{7} = \\ \\ - 13 \sqrt{7}$