Question

Find the LCD of the pair of expressions. 5/6x^7y^4, 5/3x^6y^3.

A.) 18x^6 y^3
B.) 6x^6 y^3.
C.) 6x^7 y^4.
D.) 18x^7 y^4.

Answer 1

you must have the denominators factorized. (they are already in this exercise)

the answer: "a number" \(\times x^7y^4\) (you must keep the highest powers)
for the number, you must decompose the numbers in prime numbers:
6 = 2 . 3
3 = 3

2 appears with power=1 (first fraction) and power=0 (second fraction). -> it will appear in the answer with power=1.
3 appears with a power=1 -> in the answer, you'll have \(3^1\).

answer: \(2^13^1 x^7 y^4\).

Answer 2

find "a number" is the trickiest part. it's not as simple as multiplying the two numbers.
@klepez