x^2 + 9y^2 = 37

x - 2y = -3
simultaneous equation by elimination

2 answers

elimination is usually done with linear equations. Using substitution,

x = 2y-3, so we have

(2y-3)^2 + 9y^2 = 37
4y^2 - 12y + 9 + 9y^2 = 37
13y^2 - 12y - 28 = 0
(y-2)(13y+14) = 0
(9y2+x2y)(9y2-x2y)