If x × y denotes H.C.F of x and y and x @ y denotes LCM of x and y, then the value of (72 × 84) @ 144 is:

144

x × y denotes H.C.F of x and y

x @ y denotes LCM of x and y

72 = 2³ × 3²

84 = 2² × 3 × 7

144 = 2⁴ × 3²

H.C.F of 72 and 84 = 2² × 3 = 12

Now, we have to find the L.C.M of 12 and 144

Factor of 12 = 2² × 3

So, the L.C.M of 12 and 144 = 2⁴ × 3²

∴ The value of (72 × 84) @ 144 is 144.