Algebra problem ... need help! :)

arciedee · Nov 17, 2005

I'm not used to seeing systems of equations set up this way... is it trying to say that x-y=12 AND -17/4-4x+3y=12?

Fun2, BSN, RN · Nov 17, 2005

I'm not used to seeing systems of equations set up this way... is it trying to say that x-y=12 AND -17/4-4x+3y=12?

Basically, I guess. lol

This is confusing me!!!!

arciedee · Nov 17, 2005

Basically, I guess. lol
This is confusing me!!!!

But... plugging in their answers into x-y=12... 3/4 - 5 does not equal 12. I am confused, too!

Fun2, BSN, RN · Nov 17, 2005

I'm trying to think back (to 2001)....lol

It seems you had to solve for X, then plug in to solve y. It still isn't coming out right though. :uhoh3:

.....OK, going back to try again!

Here's another one w/o fractions...and I'm still not able to figure it out:

x + y = -1 -3x -y = -13

Math.com says the answers are: X=7, y=-8.

UGGGGGH!

Ado Annie, ASN, RN · Nov 17, 2005

Ok, I've been trying to prepare myself for my 4-week Algebra retake coming up! (from B to A!!)
I need help on an Algebra problem:
x - y = -17/4 - 4x +3y = 12
+4x+y = +17/4+4x+y=12+17/4
5x=4y=48/4+17/4
Now, my final problem looks like this:
5x = 4y = 65/4
Then I tried to solve for X:
5x = 65/4
(1/5)5x = 65/4 (1/5)
x = 13/4
Then I tried to solve for Y:
4y = 65/4
(1/4)4y = 65/4(1/4)
y=65/16
When I try to solve for x or y, it doesn't come out to the answers provided by http://www.math.com.
They say the answers are: X= 3/4 y=5
I think I've reworked this problem about 20 times AT LEAST! Could someone PLEASE tell me where I'm messing up? I'm doing great so far on the other 150 equations I've completed already!
THANKS!

The math.com answer won't work with the equations you have to work with

x-y =3/4-5 does not equal 12.

So....

I think you've misinterpreted the question. x=3/4 and y=5 works for:

x-y=-17/4

-4x+3y=12

The answer to the problem as you stated it (x-y=-17/4+4x-3y=12) is:

x = -52 1/4

y = -64 1/4

Fun2, BSN, RN · Nov 17, 2005

The math.com answer won't work with the equations you have to work with
x-y =3/4-5 does not equal 12.
So....
I think you've misinterpreted the question. x=3/4 and y=5 works for:
x-y=-17/4
-4x+3y=12
The answer to the problem as you stated it (x-y=-17/4+4x-3y=12) is:
x = -52 1/4
y = -64 1/4

OK, so I tried to solve it like this now:

-4x + 3y = 12 / -4 = (x= -3 -3/4y)

Then plugged in the above x to the equation x-y=-17/4.

-3 -3/4y = -17/4

-3/4y = -17/4 + 3

-3/4y = -17/4 + 12/4

-3/4y = -5/4

(-4/3)-3/4y = -5/4 (-4/3)

y = 5/3

STILL WRONG! :uhoh3: :uhoh3: :crying2:

arciedee · Nov 17, 2005

Aha! mom2twinboys, you are absolutely correct! This all makes much more sense now (I was getting rather concerned seeing as I was a math major!).

arciedee · Nov 17, 2005

OK, so I tried to solve it like this now:
-4x + 3y = 12 / -4 = (x= -3 -3/4y)
Then plugged in the above x to the equation x-y=-17/4.
-3 -3/4y = -17/4
-3/4y = -17/4 + 3
-3/4y = -17/4 + 12/4
-3/4y = -5/4
(-4/3)-3/4y = -5/4 (-4/3)
y = 5/3
STILL WRONG! :uhoh3: :crying2:

It's easier to take the simplest equation to figure out the relationship of x and y. Here it is x - y = -17/4

So, x = -17/4 + y

Plug this into your other equation:

-4 (-17/4+y) + 3y = 12

17 - 4y + 3y = 12

-y = -5

y = 5

Then plug this back into your first equation:

x = -17/4 + 5

x = 3/4

To do it the other way (solving for x) the equation would have been:

x = (12-3y) / -4

You could plug this into x - y = -17/4 and will get the same answer.

Daytonite, BSN, RN · Nov 17, 2005

Did you copy this problem correctly? When I put this equation in function notation, (isolate y on one side and then set the resulting equation on the other side to zero) I get x = -17/20 and y = 103/80. Are you sure there isn't a second equation to go with this that would make this a system of equations?

Fun2, BSN, RN · Nov 17, 2005

THANK Y'ALL SO MUCH!

I was able to do it, and also the other problem that I wrote above, and was able to come up with the same answers as Math.com gave!

Woohoooooooo!

My future A in Algebra thanks you too!!! :chuckle

(PLEASE PRAY!!!) lol