Here is you're answer:
One of the most simple rules when solving fractions is to "find the common denominator."
Example:
-

- Find the common denominator:
- Common denominator is 2:


So, in order to solve fractions you first have to find the common denominator of each fraction, then you have to add or subtract the numerators to equal you're answer.
Hope this helps!
Find the slope (m) by using Y2-Y1/X2-X1
Y2 = -1
Y1 = 7
X2 = 4
X1 = 2
(-1 - 7)/((4-2) = -8/2 = -4
Use the point-slope formula to determine the equation. You only need to use one set of points. (2,7) in this case.
(y-Y1) = m(x-X1)
(y - 7) = -4(x - 2)
y-7=-4x + 8
y= -4x + 15
Answer:
the least common denominator is. 9