Answer:
Explanation:
The letters are easy enough.
y^3 determines that 3 ys are needed. y^2 is taken in by the cubed.
x^4 determines that 4 xs are needed. x^3 is part of x^4 and you don't need any more xs
12 and 42 are the parts that will cause the problem. Factor them both into prime factors
12: 2 * 2 * 3
42: 2 * 3 * 7
You need two 2s.
You need one 3
You need one 7
LCD = 2 *2*3 * 7 = 84