Answer:
Step-by-step explanation:
There is no solution as you have two variables and only one equation. The best you can do is solve for one variable as a function of the other.
[tex]7x^2+11y^2=40\\ \\ 11y^2=40-7x^2\\ \\ y^2=\frac{40-7x^2}{11}\\ \\ y=\sqrt{\frac{40-7x^2}{11}}[/tex]