I'm trying to use Wolfram Alpha to solve the following system of equations (for $x, y$; given $ad - bc \neq 0$) in order to confirm that I solved it correctly by hand:
$$ ax + by = 3 \\ cx + dy = -4 $$
Wolfram Alpha does not understand this syntax:
solve ax+by = 3, cx+dy = -4 for x, y
However strangely it does understand this ($y$ instead of $dy$ in the second equation):
solve ax+by = 3, cx+y = -4 for x, y
What is the correct syntax to solve this system of equations?
As said in the comments, $dy$ is the standard notation for the differential of $y$ in calculus. Using a different variable, like $hy$, would work. So does multiplying the two variables, such as $d\cdot y.$