sugam112 wrote:
GeniusRex wrote:
You can just plug the answer choices into question after picking a sample integer value for x:
Let's say x = 5;
Therefore, x(x - 1) = 5(4) = 20;
The equation now becomes : 20(x - k);
Now plug in the answer choices for the value of k:
A (-4) : 20(9) = 180; divisible by 3
B (-2) : 20(7) = 140; NOT divisible by 3
You may continue with other option choices to confirm or just stop here.
Hence the answer is choice B(-2).
Hit Kudos if this reply helped you!:)
lets say x=2
then answer changes
How?
Equation becomes : 2(1)(2 - k) = 2(2 - k);
A (-4) : 2(6) = 12;
B (-2) : 2(4) = 8;
C (-1) : 2(3) = 6;
D (2) : 2(0) = 0;...(is this where you cannot understand how it works?)
E (5) : 2(-3) = -6;
You can either use different number just for choice D or anyway you can understand B which is 8 cannot be divided by 3.