let the number be ' x '

given , least number that can be divided by 8,12 and 9 with a remainder of 3 in each case

so , 

x / 8 = n + 3 / 8

and

x / 12 = n + 3 / 12

and 

x / 9 = n + 3 / 9

where n = 1, 2, 3,4, ...........

solve the three equations and find least x value