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Question 764794: I multiplied the bottom equation by -4 to cancel out the y's then subtracted the two equations but got the wrong answer.
Solve each system of equations.
9x^2+4y^2=144
x^2+y^2=25
Found 2 solutions by ankor@dixie-net.com, DrBeeee:
Answer by ankor@dixie-net.com(22740)   (Show Source):
Answer by DrBeeee(684)  (Show Source):
You can put this solution on YOUR website! After you multiplied by -4, you should ADD the two equations.
(1) 
(2)  times -4 becomes
(3) 
If you subtract (3) from (1) you get a +8y^2 term, which you don't want. If you add (3) and (1) you get
(4)  or
(5)  or
(6)  or approx. 3
Put (5) into (2) and get
(7)  or
(8)  or
(9)  or 16.2
(10)  or approx. 4
Note that we get four solutions (intersecting points)
(16) (x,y) = {(+sqrt(8.8),+sqrt(16.2)),(+sqrt(8.8),-sqrt(16.2)),(-sqrt(8.8),+sqrt(16.2)),(-sqrt(8.8),-sqrt(16.2))}
These four point result from the ellipse (I think) of (1) and the circle (I know) of (2)
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