what does an answer of {} mean?
when I type solve(a,b,ab=76,a+b=18), I get {} as an answer.
a b = 76..........(1)
a+b=18............(2)
From (2) a = 18 - b sub into (1)
b(18 -b) =76
18b - b^2 =76 re-arrange
-b^2 + 18b - 76 =0, solve for b
b =9 + sqrt(5), and b=9 - sqrt(5) sub into (2)
a + (9 + sqrt(5) =18
a = 9 - sqrt(5) and a =9 + sqrt(5)
