When we have two radicals, we can multiply what's inside and combine, but let's break down the 108 and 168.
108 = 4(27) = 22(33)
168 = 8(21) = 23(3)(7)
Soooo, 108(168) = 25(34)(7).
The square root of 25 is √(24(2)) = 2√2
The square root of 34 is 32 = 9
The square root of x8 is x4.
√y5 = √(y4y) = y2√y
Putting it all together...
18x4y2√2y
