You can put this solution on YOUR website! the least common denominator would be (a)(2b). if you were to work the problem the best advice for thing like this I can give is to work it in the following manner.
5/a-7/2b
((a)(2b)* 5/a)- (7/2b *(a)(2b)) in the first number the a's would cancel
in the second the 2b would cancel
5a-14b I multiplied the denomonator that was left after the cancelling by the number. do you see what I did? This tip works great for solving problems with variables, large numbers, ect...
You can put this solution on YOUR website! The lcd is (a)(2b)
(a)(2b)5/a - 7/2b (a)(2b)=
Cancel out the a for 5/a and cancel out the 2b for 7/2b
Your left with (2b)5 - (a)7=
10b-7a
(
