please help me

M

maths_arghh234

Junior Member
Joined
Nov 8, 2009
Messages
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okay so .. i've been given a AS level paper and we went through the first 2 questions in class only on part d onwards he was going too fast and i couldn't read his writing it's finding the coordinates of a point on a graph using simultaneuos equations .. i could read his answers (i think anyway ) what he had was y=5 x=2

and the equations =
1) y+2x=9
2) 2y -x =8 i tried the first part to find y and keep coming up with 0.42.... and then breaking down ...please help me ..this was one of the things i thought i COULD do

..i know i've just writen a stats problem up but i was doing this just to keep working .

my working out is like this

1) y+2x=9
2)2y-x=8 <----x2 =3) 4y-2x=16
3)-1)
= 3y = 7 or -3y=-7 and then that comes up with 0.42... or - 0.42.....
 
Hi Matey, arrgh.

Well, I don't understand the work shown, but I see that you multiplied the second equation by 2, so I'm going with the elimination method.

Now add the following two equations together, to get an equation in which the variable x is eliminated.

Code: 
       y + 2x =  9
+     4y - 2x = 16
---------------------

The sum of these two equations is an equation that contains only y. Solve for y, and then go back to one of the original equations to determine x.

Cheers ~ Mark
 
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