need help!

sqrt (10x² )    =    x sqrt 10     

or maybe     sqrt (10 x 2 )   = sqrt 20 =  sqrt (4*5) = 2 sqrt 5

$\sqrt(10*2) \\ \\\sqrt(20) \\ \\\sqrt(4*5) \\ \\2\sqrt(5)$

Solution:

$2\sqrt(5)$