Do you mean LCM (Least common multiple)
Answer:x=1
Step-by-step explanation:
y=y
y = -x + 10
y = 7x + 2
-x+10=7x+2
10=8x+2
8=8x
x=1
Keep the denominators the same and subtract the numerators. So for example in your example:
7/8 - 3/8
Leave the 8 alone. Subtract 3 from 7.
7 - 3 = 4
So answer is:
4/8
Sometimes they may have to simplify the answer, and in this case, 4/8 could be simplified to 1/2