(m + 4) (m – 10) = 0

(iii) (m + 4) (m – 10) = 0

Sol. (m + 4) (m – 10) = 0

∴  m(m – 10) + 4(m – 10) = 0

∴  m² – 10m + 4m – 40 = 0

∴  m² – 6m – 40 = 0

Now it is in the standard form of ax² + bx + c = 0