combine into a single expression
how do i do this
3/x+4/y

Question

combine into a single expression
how do i do this 
3/x+4/y

anonymous · Answer

Common denominators...just like if it were numbers. If you had 2/3 + 1/2  What would you do?

agent0smith · Answer

Get common denominators for$$\Large \frac{ 3 }{ x }+\frac{ 4 }{ y }$$multiply the left one by y/y, and the right one by x/x, to get a common denominator xy
$$\Large \frac{ 3 }{ x }*\frac{ y }{ y }+\frac{ 4 }{ y }*\frac{ x }{ x }$$

anonymous · Answer

3y/xy+4x/yx?
so it would be 3y+4x/xy?

jhonyy9 · Answer

yes just cross multiplie

jhonyy9 · Answer

Ok ?

jhonyy9 · Answer

so because the common denominator is xy

ok ?

jhonyy9 · Answer

and will get (3y+4x)xy

skullpatrol · Answer

You need to write your answer like this: (3y+4x)/xy 
not 3y+4x/xy, or use $$\frac{3y+4x}{xy}$$

anonymous · Answer

i understand what all of you arre saying but i never totally understood the concept of common denominators

anonymous · Answer

actuallly i get it thanks alot everybody :D its means alot!!!

agent0smith · Answer

Just look for what is "missing" in each denominator, to get a common denominator.

anonymous · Answer

u mean like how in one we had x and the other we had y but thy werent joined?

agent0smith · Answer

Yes, on one denominator you only had an x, so it's missing a y. In the other, you only had a y, so it's missing an x, so to get them the same, you have to make the denominator xy for both.

anonymous · Answer

okay that makes sense thank you so much :)