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need_help!
Group Title
Find an ordered pair that is a solution of the system
4 2 1
3 2 3
x y
x y
+ = 
 =
 2 years ago
 2 years ago
need_help! Group Title
Find an ordered pair that is a solution of the system 4 2 1 3 2 3 x y x y + =   =
 2 years ago
 2 years ago

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need_help! Group TitleBest ResponseYou've already chosen the best response.1
What the..? Wait.
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
4x+2y=1 3x2y=3
 2 years ago

Hero Group TitleBest ResponseYou've already chosen the best response.1
Add the equations together and what do you get?
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
How do I add them?
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
Combine all of the like terms. Since you know that 4x+2y=1 and 3x2y=3, you also know that 4x+2y + 3x 2y = 1 + 3
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
so, x=2/7 ?
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
now how do you get y when x=2/7?
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
umm, i think you just substitute right? O.o
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
yep =) [just plug x=2/7 back into either equation]
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
Yay! This is easy =D Thank youu.
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
No problem. Now the general way to solve these types of problems (systems of equations), is to solve for one variable first, and then substitute back into the other equation. To do this, you mus have a separate equation for each unknown variable  for example in this problem there are two equations and two unknowns.
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
Yes I get it! But for example you have like: 4x+4y=1 3x2y=3 What do you do here? you can't cancel the 'y' or 'x' out
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
well, you actually can if you know a small trick.
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
if you know that 3x  2y = 3, you can multiply both sides by the same number and the equation will still be true (equivalent)
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
in this case, I can multiply both sides by 2
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
so 2(3x 2y) = 2*3
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
Now you can cancel out all of the y's by adding the two equations
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
4x + 4y = 4 6x  4y = 6
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
Aooh! *smart* :P :D
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
I like it! Thanks a lot for the help.
 2 years ago

chris Group TitleBest ResponseYou've already chosen the best response.2
No problem. There are other ways to solve these types of problems, but just ask here when you find a case where it's hard to find a way to cancel out =). good luck!
 2 years ago

need_help! Group TitleBest ResponseYou've already chosen the best response.1
btw, the ordered pairs are : (0,5/14) and (2/7,0) ?
 2 years ago
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