Is X positive? Where L and X are integers 1. X^2 = 1 2. LX +

Question

Is X positive? Where L and X are integers

1. X^2 = 1
2. LX + X^2L = 12

twixt · Answer

Go for C.

1 > X = 1 or -1
2 > X>-1 or X<-1
Only X=1 is compliant with both statements

chanatty · Answer

(1) X = 1 or -1 , insuff.

(2) Assume L = 1; X + X^2 = 12 or X^2 + X - 12 = 0
 (X+4)(X-3) = 0 So, X = -4 or 3, insuff.

Together; X^2 = 1
In statement(2); LX + (X^2)^L = 12 or LX + 1 = 12
So, LX = 11 --> X will be + if L is + and will be - if L is -
The answr is E.

hardworker_indian · Answer

C.

I gives +1 or -1. Insufficient.
II depends on L. Insufficient.

Together x^2 = 1
So, II becomes LX+L = 12 
= L(X+1) = 12
Here x cannot be -1 since that would lead to 0=12, so x = 1
Ans: Yes. C.

sdanquah · Answer

I don't see how you got LX+L = 12 , given that x^2 =1 unless the question stem is LX + (x^2)L, but I don't see it that way. I see it as LX + x^2L , which means X is raised to the power 2L, which would make E the best choice

venksune · Answer

Pardon the ambiguity. Yes, I meant LX^2. My bad. really sorry, it is ambiguous. OA is C. 

1.X^2=1 => X=+1 or -1. So, Insuff.
2. LX + LX^2 = 12 =>LX(1+X)=12 => X=-1, then LX(1+X) = 0. So, Insuff.

Combining both, if X=1, it will satisfy both conditions. So, C.

Is X positive? Where L and X are integers 1. X^2 = 1 2. LX +

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards