View Full Version : sat math question of the day

10-19-2013, 06:00 PM
If -4<a<1, then which one of the following is negative?
(I) (a+4)(a-1)
(II) (-4-a)(a-1)
(III) (-4-a)(1-a)

(A) I only
(B) II only
(C) III only
(D) I and II only
(E) I and III only


10-19-2013, 06:01 PM
All of the choices can be interpreted as quadratic inequalities with roots a=-4 \ or \ a=1 . The leading coefficient(s) for (I) and (III) are positive while for (II) is negative.

Therefore, for (I) and (III) we have the following sign diagram


While for (II) we have the following sign diagram


Therefore the correct answer is (E).

Hope these help!!

10-19-2013, 06:02 PM
Thanks a lot for your reply!!;)