Help from the math brains...

[03cobrablack]

Can you solve these and if so please tell me how you did it!!!!


X and Y must be the same for each system of eqausion.
problem one

3X+7y=-20
7x -6y= -2

problem two

-3x+5y=-9
5x-4y=2

problem three

-2x-5y=-5
5x-3y=-14

 

[sikklightning04]

TTT im not sure, i feel retarted. Im in college getting a 3.0 speak two languages and cant do basic algebra.

 

[05 Roush]

I can help you solve these.

First, get the two equations to equal the same thing. For example in your first equations, you have a formula = -20 and another formula = -2.

Which one is the highest? I'll give you a hint: -20. What do you have to multiply the entire second equation with to = -20?

Now that you have a common answer, set the two equations equal to each other (something like x +y = x - y). Take the x and y values and add/subtract accordingly. Hope this helps.

 

[RookieBeotch]

last time i checked -2>-20
unless you had a different meaning in mind for highest?

i think you can solve those types of equations by substitution, as well as by graphing it.

 

[sikklightning04]

Now that you have a common answer, set the two equations equal to each other (something like x +y = x - y). Take the x and y values and add/subtract accordingly. Hope this helps.

this is the way..

 

[05 Roush]

last time i checked -2>-20
unless you had a different meaning in mind for highest?

i think you can solve those types of equations by substitution, as well as by graphing it.

Ignore the (-). All that does is position the number. What's important here is that 2 goes into 20.

Now, let's say it was -2 and -21. In this case, 21 is not evenly divisible by 2. Multiply the two together and use this as the common answer. The same logic applies. as before, but this time you'd have to multiple both equations by the correct multiplier.

 

[03cobrablack]

Cool thanks guys, this is acually for my wife but I figure the sonner she gest done, the more chance I have of a little "quality time." and I didn't have a clue as to how to solve them...

I gave her your explination 05Roush, and she is working on them with out cussing so I think it helped...

 

[05 Roush]

Cool thanks guys, this is acually for my wife but I figure the sonner she gest done, the more chance I have of a little "quality time." and I didn't have a clue as to how to solve them...

I gave her your explination 05Roush, and she is working on them with out cussing so I think it helped...

Hope it does help. Sometimes I don't explain myself very well, but one thing I do know is that these formulas are a piece of cake with the "get them to equal the same thing" method.

 

[Whizzle]

Can you not just set y=x to get y in terms of x and plug it back in?

 

[05 Roush]

Can you not just set y=x to get y in terms of x and plug it back in?

That will only answer one of the possible solutions. Remember, x and y can be any number. If x=y, what happens when the following conditions apply?:

x < y
x > y

 

[91GT]

You have to solve Y in terms of X. So in the first question, if you solve the first equation for Y, you get: Y=(-20-3X)/7

You then take that in a "plug" it back in to the first equation, so you get:
7X-6((-20-3X)/7)=-2

After that, you can simplify, and you only have 1 unknown, X.
You can solve for either X or Y and then just sub back in. You can have as many unknowns as you have equations.
Sorry if this is confusing, but it is somewhat difficult to teach math over the internet.

 

[SHONOFF98]

Im drunk but I just figured in the first equation that y= about 2.0298

 

[05 Roush]

Im drunk but I just figured in the first equation that y= about 2.0298

The answer to the first one is as follows:

3X+7y=-20
7x -6y= -2 ==> 70x - 60y = -20

3x+7y=70x-60y
67y = 67x
y=x
3x + 7x = -20
10x = -20
x=y=-2

It's more writing doing it this way, but it's faster and less proned to errors.

 

[SHONOFF98]

Yea that makes sense, I took a different approach to it and now that I look at what I did I had it right just made a slight mistake in the calculation (I think it was the beer)

21x + 49y = -140
-21x + 18y = 6

You can cancel the x's and you have 67y = -134 which y = -2 then


Last night I got -136 instead of -134 I dont know who wants to do math after some beers but it was fun

 

[SHONOFF98]

dp

 

[CalcVictim]

copy and paste your equations in here
http://wims.unice.fr/wims/en_tool~linear~linsolver.en.html



I am not sure how old your wife is but unless she is in the 7th grade or below she really should know how to solve this.

 

[traktrbeam]

Math sucks.

 

[2slow4u]

my brain hurts lol

 

[snake134]

for the first one i got y=2 and x= -11 1/3......correct me if im wrong

 

[LS1PUSSOUT]

those are very basic and simple algebra problems