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:

144 504 210 420

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.