(x- 1)(x-4)a=(x+4)(x-4)

There is no solution for any A.

Look at the coefficient of a first. If you take 0 and the right side is not 0, he has no solution to any A.

X takes 1, which is a solution.

On second thought, when x takes 4 from 4, it always holds.

13 minutes ago, when taking -4, left non-0 and right 0 never wanted to wait.

12 minutes ago, so X can choose B with 1 and -4.