Can someone explain where I went wrong? I did not use the shortcut method. I solved for x and y where I got x=1 and y=2. In the solution greg subtracts the equations, is it something we can do? since we only add the equations in the shortcut.
You didn’t post your work so it’s impossible atm
Why not?
Subtracting is just adding by the inverse element. Also, rather than memorizing certain tricks in some shortcut, you should try to rationalize what works and what doesn’t.
Figured it out, I made a calc error and hence got y=2 instead of y=-2. Thanks for your response!