Answer:
x = [(m - n +/-√ (n^2 + m^2 + 2nm)]/2.
Explanation:
x^2+nx-mx-nm=0
x^2 + (n - m)x - nm = 0
Using the quadratic formula:
x = [-(n - m) +/- √((n - m)^2 - 4*-nm)) / 2
= [(m - n +/- √ (n^2 + m^2 - 2nm + 4nm)]/2
= [(m - n +/-√ (n^2 + m^2 + 2nm)]/2