Question 254907
In order to graph, you need to solve for y



{{{9x^2+25y^2=225}}} Start with the given equation.



{{{25y^2=225-9x^2}}} Subtract {{{9x^2}}} from both sides.



{{{y^2=(225-9x^2)/25}}} Divide both sides by 25.



{{{y=""+-sqrt((225-9x^2)/25)}}} Take the square root of both sides (don't forget about the plus/minus)



{{{y=sqrt((225-9x^2)/25)}}} or {{{y=-sqrt((225-9x^2)/25)}}} Break up the plus/minus to form two separate equations.




So the two equations that you would enter into your calculator would be {{{y=sqrt((225-9x^2)/25)}}} and {{{y=-sqrt((225-9x^2)/25)}}}



If you enter them in, you should get the graph:


{{{ drawing(500, 500, -10, 10, -10, 10,
 graph( 500, 500, -10, 10, -10, 10,sqrt((225-9x^2)/25),-sqrt((225-9x^2)/25))

)}}}


Take note that the red graph is {{{y=sqrt((225-9x^2)/25)}}} and the green graph is {{{y=-sqrt((225-9x^2)/25)}}} which both form the graph of {{{9x^2+25y^2=225}}}