Find the LCD that would eliminate the fractions in this equation.

4n-1/7=5/7

Multiply the whole fraction by seven. You get 28n-1=5 Gathering the terms, 28n=6 Dividing by 28, n=3/14 I'm not sure what you mean by LCD, but you could, alternatively, Add 1/7 to both sides, 4n=6/7 Multiply the left-hand side by 7/7 (you can do that because it's equal to one, so the equality is preserved), 28n/7=6/7 Multiply by seven, 28n=6 And divide by 28, n=6 / 28