If for non-zero x

Given x ≠ 0 and a ≠ b such that

..... (1)

Substituting in place of x, we get

.....-- (2)

On adding equations (1) and (2), we get

..... (3)

On subtracting equations (1) and (2), we get

..... (4)

On adding equations (3) and (4), we get

Thus,