How do you graph 4x^2+9y^2+24-18+9=0?

1 Answer
Sep 8, 2016

(see below)

Explanation:

Note: I am assuming that the equation should have been:
color(white)("XXX")4x^2+9y^2+24color(red)(x)-18color(red)(y)+9=0

The standard form of an ellipse is
color(white)("XXX")((x-h)^2)/(a^2)+((y-k)^2)/(b^2)=1

with center at (h,k),
radius on X-axis =a, and
radius on Y-axis=b

Converting the (assumed) equation into this form:
color(white)("XXX")4(x^2+6x)+9(y^2-2y)=-9

color(white)("XXX")4(x^2+6x+9)+9(y^2-2y+1)=-9+4xx9+9xx1

color(white)("XXX")4(x+3)^2+9(y-1)^2=36

color(white)("XXX")((x+3)^2)/(3^2)+((y-1)^2)/(2^2)=1

So we need to draw an ellipse with center at (-3,1),
a radius of 3 parallel to the X-axis, and
a radius of 2 parallel to the Y-axis.

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