On the equation 2-ax = (6 + x) I of X, which has real roots, we can find the value of real number a

On the equation 2-ax = (6 + x) I of X, which has real roots, we can find the value of real number a

2-ax=(6+x)i
The result is: a = (2 - (6 + x) I) / X
Because a is a real number, then I does not exist, (6 + x) = 0, x = - 6
Then a = - 1 / 3