#1

Ok so im subtracting fractions such as this one:

4/y-4 - y/y-4

This is what i got:

4-y/y-4

but the book says the answer is -1.

Im thinking something must be done like factoring so some help please?

4/y-4 - y/y-4

This is what i got:

4-y/y-4

but the book says the answer is -1.

Im thinking something must be done like factoring so some help please?

#2

Tis the same thing

#3

So any suggestions?

#4

My only guess is add 4 to both sides, giving you -y/y which gives -y. Which I suppose could be -1

#5

I think you have to factor out something.

y-4 is not the same as 4-y

y-4 is not the same as 4-y

#6

if you take the top and multiply by -1, you get -1(4-y)=-(y-4) and -(y-4)/(y-4)=-1

EDIT: Basically you're factoring out a '-1' out of the top.

EDIT: Basically you're factoring out a '-1' out of the top.

#7

My only guess is add 4 to both sides, giving you -y/y which gives -y. Which I suppose could be -1

it wouldn't work as your dividing by 4

#8

Multiply the top by -1 twice (which is legit, because all you're doing is multiplying it by 1). so it would be like:

-1(y-4)/y-4

Which as you can see, the two cancel, leaving only -1.

-1(y-4)/y-4

Which as you can see, the two cancel, leaving only -1.

#9

You factor out the -1 in the top half...

(4-y) --> -(y-4)

...

(4-y) --> -(y-4)

...

#10

You can change the denominator to -(4-y). so you get 4-y/-(4-y) which equals -1.

#11

if you take the top and multiply by -1, you get -1(4-y)=-(y-4) and -(y-4)/(y-4)=-1

EDIT: Basically you're factoring out a '-1' out of the top.

if you multiply it wouldnt you get -4+y?

#12

Oh, right. I blame it on being slightly drunk.it wouldn't work as your dividing by 4

#13

From What You Got 4-y/y-4 ...opposite Make A -1 Ex. (4-y)/(y-4) Opposite Signs And When You Do That You Get -1....WHAT YOU GOT IS RIGHT BUT YOU PROBALLY HAVE TO SIMPLIYFIE IT

#14

if you multiply it wouldnt you get -4+y?

Yes and -4+y=y+(-4) (addition is commutative)

#15

Yes and -4+y=y+(-4) (addition is commutative)

YES YES IM AN IDIOT!

Thank you sir!

#16

*thumbs up* you said it

#17

y/y=1, just as 4/4=1 or 123/123=1

so 4-1-4= -1

so 4-1-4= -1

#18

factor out negative one from the bottom, you get (4-y)/[-(-y+4)]

then the top and bottom cancel leaving 1/-1, and that's negative one!

then the top and bottom cancel leaving 1/-1, and that's negative one!