Lets try one way to solve this system. First, we want to isolate one of the unkown, lets choose y, so we need to remove x from an equation. In order to remove x from an equation, thats what we are going to do :
Line 1:
(3x² - 5y²) * 2 = 22 * 2
6x² - 10y² = 44
We simply multiplied Line 1 by the number 2, this doesn't change anything on the nature of Line 1.
Line 2:
(2x² + 4y²)*3 = 22*3
6x² + 12y² = 66
We simply multiplied Line 2 by the number 3, this doesn't change anything on the nature of Line 2.
Solving your system of equations is exactly the same thing as solving this new system of equation :
6x² - 10y² = 44
6x² + 12y² = 66
It is exactly the same. But it is easier now, because we can remove x from the equation simply by subtracting line 2 from line 1 :
L1 - L2 :
(6x² - 10y²) - (6x² + 12y²) = 44 - 66
6x² - 10y² - 6x² - 12y² = - 22
- 22y² = - 22
y² = 1
y = + 1 or y = - 1
We know have the value of y, we just have to replace it in the equation to solve the entire system :)
3x² - 5y² = 22
since y² will always be equal to one, wether y = 1 or y = - 1, we can write :
3x² - 5 = 22
3x² = 22 + 5
3x² = 27
x² = 27/3
x² = 9
x = + 3 or x = - 3
So the solutions are the following couples in the form (x,y) :
S = { (3 ; 1) , (-3;1) , (3 ; - 1) , (-3 ; -1))
Good Luck