Answer:
The formula of LCM is LCM(a1,a2,a3....,an) = ( a1 × a2 × a3 × .... × an) / GCF(a1,a2,a3....,an) x common factors(if more than 2 numbers have common factors).
We need to calculate greatest common factor of 7,11,18 and common factors if more than two numbers have common factor, than apply into the LCM equation.
GCF(7,11,18) = 1
common factors(in case of two or more numbers have common factors) = 1
GCF(7,11,18) x common factors =1 x 1 = 1
LCM(7,11,18) = ( 7 × 11 × 18 ) / 1
LCM(7,11,18) = 1386 / 1
LCM(7,11,18) = 1386
∴ Least Common Multiple of 7,11,18 is 1386