Find all the prime factors of the three numbers. pick up the common factors, ONCE, then pick up the non-common factors one by one, multiply the factors, the product is the least common factor. example: the least common multiple of 6, 8, and 15 6=2*3 8=2*2*2 15=3*5 Note: do not write 8 into 4*2, because 4 is not a prime number. you have to break the number down to prime factors only. Notice that 6 and 8 have a common factor 2, so pick up the 2; 6 and 15 have a common factor of 3, so pick up the 3. those are the only two shared factors, so 2×3 now pick up whatever is not shared: the two 2s for 8 and the 5 for 15 is not shared, add 2, 2, and 5 to the multiplication: 2×3×2×2×5=120 120 is the least common multiples of 6,8, and 15
this is basically how it is done. I believe you can explain better in your own words.
There are actually 2 answers, 3 and -3. Although if you put it in a calculator, it would show "math error" or undefined. That's because the index is even (4) and the radicand is negative (-81)
