Question

I need help with lcd!!!!

Answer 1

What aspect of the process is confusing you?

Answer 2

The lcd of 1/6 1/10 1/18 1/21????

Answer 3

Ok, so there are a few techniques you can use here. You can either attempt a brute force method of simply listing all the multiples of 6, 10, 18, and 21. You can factorize each of the denominators, see which factors they have in common, then multiply each one by the factors it is missing, etc.

Answer 4

With so many different denominators, I recommend the factoring method.

Answer 5

So what are the factors of 6, 10, 18, and 21 (individually).

Answer 6

6 = 2 * 3
10 = 2 * 5
18 = 2 * 3 * 3
21 = 3 * 7

lcd = 2 * 3 * 5 * 3 * 7

Answer 7

1 2 3 6

1 2 5 10
1 2 3 6 9 18
1 3 7 21

Answer 8

find the prime factors of each number and then find the smallest set of common prime factors.

Answer 9

thanks guys you rock!

Answer 10

why is there two threes in the equation?

Answer 11

of 18

Answer 12

3, 3, 2

are all of the prime factors of 18. basically 3 * 3 * 2 = 18. you have to take them into account when finding the lcd because lcd / 18 should give you a remainder of 0.