LCD(15, 7, 8) = 840.
The LCD is 56. The two have no common factors, so the LCD is their product, 7 x 8 =56
LCD is 24
Prime factor each number. 12= 2x2x3 8=2x2x2 7=7 Multiply the factors the MOST it was used in any number. 2x2x2x3x7=168
280
168
56565656
280
8.
8
LCD(8, 21, 7) = 168.
LCD(10, 8, 7) = 280.