Looking for a pattern in a math riddle Looking to find a pattern but no idea how:

$12\mathop{\square}21 = 86$,

$13\mathop{\square}31 = 192$,

$14\mathop{\square}58 = 389$,

$14\mathop{\square}94 = \ ?$
This problem is not clearly defined. One of infinitely many ideas is the ansatz

$$x\square y := x\cdot a +b+ c\cdot y$$ 

leading to 3 equations, which can be solved giving

$$a=\frac{892}{17}, b=\frac{-11153}{17}, c=\frac{91}{17}.$$

Now, what is $$14\square 94=?$$
This problem is not clearly defined. One of infinitely many ideas is the ansatz

$$x\square y := x\cdot a +b+ c\cdot y$$ 

leading to 3 equations, which can be solved giving

$$a=\frac{892}{17}, b=\frac{-11153}{17}, c=\frac{91}{17}.$$

Now, what is $$14\square 94=?$$