Question

what is the LCM of 15x,12x? I am tutoring a student who says that one simply drops the x? That can't be right

Answer 1

You can't drop the x, since you don't know what its factors compose of. The lcm is instead \[\frac{12x \cdot 15x}{gcd(12x, 15x)}\] which should make enough sense; you need to multiply 12x and 15x together to find a common denominator, then divide by the greatest common denominator of that product.

Answer 2

the LCD is the smallest number that has the factors of 12x and 15x

Answer 3

the factors (prime) of 12 is 2*2*3 and 15 is 5*3 so the LCD must be 2*2*3*5 or 60

Answer 4

hello

Answer 5

all

Answer 6

I forgot to include the x !! 60x

Answer 7

You can not simply drop the x!