Question

How do you solve the system `x^2 - 2y = 1`, `x^2 + 5y = 29`?

Answer 1

`absx = 3`
`y = 4`

Explanation:

You can substract the 1st line to the 2nd one, which will make `x^2` disappear. So the 2nd line is now `7y = 28` and you now know that `y = 4`.

You replace `y` by its value in the 1st line of the system :

`x^2 - 2y = 1 iff x^2 - 8 = 1 iff x^2 = 9 iff abs(x) = 3`