what does an answer of {} mean?
when I type solve(x,y,xy=76,a+b=18), I get {} as an answer.
+130075 You have 4 variables but only 2 equations....we can't derive any solutions from this
{ } means no solutions exist
Are you sure this isn't meant to be
xy = 76 and x + y = 18 ???
If so....... xy = 76 ⇒ y = 76/x
Putting this into the second equation, we have
x + 76/x = 18 multiply through by x
x^2 + 76 =18x rearrange as
x^2 - 18x + 76 = 0
The two solutions are x = 9 - √5 and x = 9 + √5
Whichever you choose for x, y will be the other one
