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anonymous
 one year ago
Given the system of equations:
y = 3 x + 9
4 x − 9 y = − 8
Find the ycoordinate of the point of intersection of the two lines.
anonymous
 one year ago
Given the system of equations: y = 3 x + 9 4 x − 9 y = − 8 Find the ycoordinate of the point of intersection of the two lines.

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TheSmartOne
 one year ago
Best ResponseYou've already chosen the best response.1do you know the method of substitution?

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0method of substitution is when you plug one equation into another?

EmmaTassone
 one year ago
Best ResponseYou've already chosen the best response.1If you want to see the intersection point you have to look for the point that comply both equation. e.g. if I have this system: a) x+y=1 b) xy=0 and i want to find now ycoordinate that comply the equations, so from b) we have x=y so we replace this information in a) then : x+x=1 ==> 2x=1 ====> x=1/2 since x=y ===> Y=1/2 in my example

TheSmartOne
 one year ago
Best ResponseYou've already chosen the best response.1yes, you can plug in the first equation in to the second one

TheSmartOne
 one year ago
Best ResponseYou've already chosen the best response.1and then solve for x

TheSmartOne
 one year ago
Best ResponseYou've already chosen the best response.1then plug in the value you got for x into any of those equations and solve for y

EmmaTassone
 one year ago
Best ResponseYou've already chosen the best response.1you can work analogous in your problem

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0which one is easier? I am not sure where emma got the 2x from here example. came from. If I plug one equation into another do I plug it into the front or back?

EmmaTassone
 one year ago
Best ResponseYou've already chosen the best response.1i used the substitution method xD i just plug the y=x in the other equation

EmmaTassone
 one year ago
Best ResponseYou've already chosen the best response.1you have to clear a variable first and then plug that variable in the other equation

EmmaTassone
 one year ago
Best ResponseYou've already chosen the best response.1I can do the example again exaplining it better if you want

anonymous
 one year ago
Best ResponseYou've already chosen the best response.0I am not sure where I put the y= 3x + 9 ... into 4x9y=8

EmmaTassone
 one year ago
Best ResponseYou've already chosen the best response.1Here its another example with this system: \[4x+6y=0\] \[5x=3y+2\] So, what you have to do is clear one variable from any equation, im going to clear variable x from first equation:\[4x+6y=0 \rightarrow 4x=6y \rightarrow x=\frac{ 6 }{ 4 }.y\] Once we cleared x, we plug it in the second equation:\[5x=3y+2\] replacing it: \[5(\frac{ 6 }{ 4 }.y)=3y+2\] \[\frac{ 30 }{ 4 }.y=3y+2\] \[\frac{ 30 }{ 4 }y3y=2\] \[\frac{ 21 }{ 2 }y=2\] Finally:\[y=\frac{ 4 }{ 21 }\]
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