Adding & Subtracting more complex rational expressions

When adding or subtracting more complex rational expressions like unlike denominators , you have to find the least common denominator, then just add or subtract normally.


2y =2 * y
3y^2 = 3 * y * y
Use each prime factor the greatest number of times
it appears in each.
LCD: 2 * 3 * y * y or 6y^2

Change each rational expression into an equivalent
expression with the LCD by multiplying the top and bottom by the same numbers/variable like this:

5/2y + 4/3y^2 = 5(3y)/2y(3y) = 4(2)/3y^2(2) which becomes 15y/6y^2 + 8/6y^2   which equals 15y+8/6y^2.