JAMB - Mathematics (1991 - No. 19)
Which of the following is a factor of rs + tr - pt - ps?
(p - s)
(s - p)
r - p)
r + p)
คำอธิบาย
rs + tr - pt - ps = rs - ps - tr - pt
= (r - p)s + (r - p)t
= (r - p)(s + t),
hence r - p is a factor
= (r - p)s + (r - p)t
= (r - p)(s + t),
hence r - p is a factor