so you rewrite the fractions as (-2y)/(xy) + (3x)/(xy)

that = (3x – 2y)/xy.

12. the common denominator is x(2)y,

so the fraction will be 5x/x(2)y – 7y/x(2)y + 9x(2)/x(2)y that will = (9x(2) + 5x – 7y)/x(2)y

13. when multiplying you look for factors that can be canceled out, the 5 and 15, 5/5 = 1 15/5 = 3, so the fractions will be -a/7b(2) times -8ab/3. Now multiply the tops, then multiply the bottoms.

=8a(2)b/21b(2). We can do some canceling with the “b”. so you end up with 8a(2)/21b

14. When you divide fractions you turn the second one upside down and then multiply.

So the problem will be 6x(2)y/11 times 22/9y(2) =

We can do some canceling. 11/11 = 1, 22/11 =2,

6/3 = 2, 9/3 =3. So now the problem will look like this 2x(2)y/1 times 2/3y(2). Again multiply the tops then multiply the bottoms = 4x(2)y/ 3y(2), we can cancel the y = 4x(2)/3y.

Hope this is all clear.