Question

(-radical din 14)•(4radical din7)-(5radical din 6)•(-radical din 3)​

Answer 1

$( - \sqrt{14} ) \times (4 \sqrt{7}) - (5 \sqrt{6} ) \times$

$\times ( - \sqrt{3} ) =$

$= ( - 4 \sqrt{14 \times 7} ) - ( - 5 \sqrt{6 \times 3} )$

$= - 4 \sqrt{2 \times {7}^{2} } - ( - 5 \sqrt{2 \times {3}^{2} } ) =$

$= - 4 \times 7 \sqrt{2} - ( - 5 \times 3 \sqrt{2} ) =$

$= - 28 \sqrt{2} - ( - 15 \sqrt{2} ) =$

$= - 28 \sqrt{2} + 15 \sqrt{2}$

$= - 13 \sqrt{2}$