Question

Solve by elimination:

9x2 + y2 = 85
2x2 - 3y2 = 6

Answer 1

Eliminate y by multipling both sides of the first equation by 3 and then add the equations together:
27x^2 +3y^2 = 255
2x^2 - 3y^2 = 6
--------------------
-29x^2 = 261
x^2 = 9
Knowing x you can now solve for y by plugging x into either equation.\[\{\{x\to -3,y\to -2\},\{x\to -3,y\to 2\},\{x\to 3,y\to -2\},\{x\to 3,y\to 2\}\} \]

Answer 2

thanks!!

Answer 3

My mistake. The negative sign of -29x^2 should not be there.

Answer 4

Thank you for the medal.