Wednesday

October 1, 2014

October 1, 2014

Posted by **Emily** on Monday, November 23, 2009 at 11:21pm.

34. x^2 + 25y^2 - 6x - 100y + 84 = 0

(Hint: Complete the squares in x and y. Begin by writing the equation in this form: (x^2 - 6x + ___) + 25(y^2 - 4y + ___) = -84.)"

==> I used the hint that came with the problem, but as I tried to solve the equation into the general form for an ellipse, I was getting negative denominators, which would make a and b contain imaginary numbers. Does anyone know how to solve this? Any help is greatly appreciated! :)

- Precalculus -
**Reiny**, Monday, November 23, 2009 at 11:38pmx^2 + 25y^2 - 6x - 100y + 84 = 0

x^ - 6x + 9 + 25(y^2 - 4y + 4) = -84 + 9 + 100

notice in the y expression, I added 4 to the inside, but that was multiplied by 25, so I had to add 100 on the right side.

(x-3)^2 + 25(y-2)^2 = 25

(x-3)^2/25 + (y-2)^2 = 1

so a^2 = 25, and b^2 = 1

take it from there

- Precalculus -
**Emily**, Monday, November 23, 2009 at 11:59pmOhhhhh!!!!! This totally makes sense. I forgot to multiply the 4 by 25 before bringing it over to the other side. Thanks so much!! :D

**Answer this Question**

**Related Questions**

Pre-calculus - For the ellipse with equation 5x^2+64y^2+30x+128y-211=0, find the...

Math - Find the vertices, center, asymptotes, and foci of the ellipse and sketch...

maths - Given that the ellipse x^2/a^2 + y^2/b^2 =1 has foci at(+/-ae,0)where e ...

Math/Algebra - Find the standard equation of an ellipse with the given ...

Algebra 2 - Choose the equation that best represents an ellipse for the given ...

Math - Find the center, vertices, foci, and eccentricity of the ellipse. 9x^2 + ...

algebra 2 - Graph the equation. Identify the vertices, co-vertices, and foci of ...

AlgebraII - Choose the equation that best represents an ellipse for the given ...

algebra - Choose the equation that best represents an ellipse for the given foci...

Pre-calculus-ck answers - Identify the graph of the equation 4x^2-25y^2=100. ...