If you have two fractions like that, you can write
as
Double-click my expressions there to see how I got the bigger fractions. Another command that is useful is the dfrac command.
Express x in terms of y for the expression:
and hence evaluate:
So i express x in terms of y in the first expression and get:
And then proceed to evaluate the second part of the question as follows:
Multiply here by the LCD 8:
Which gives:
The final answer in the book is:
So do i just cancel the eights and y's in my above answer? Also is my method in evaluating correct? Any help would be great. Thanks!
P.S why does my latex come out so small :?
Remember that algebra is essentially arithmetic with symbols.
You learned long ago that "to divide fractions, invert the divisor and multiply":
which is how Ackbeet wrote your fraction. Now you should be able to see easily that you can cancel the "y" and "8" terms.