Hi All,
It looks like a number of the explanations take a more complex approach than what is needed. This question is based on FOIL-ing and Factoring rules; even though it looks a little "tough", the same rules still apply...
We're given 2X^2 + 5X = 12
We can rewrite that as....
2X^2 + 5X - 12 = 0
Now let's break this into it's two 'pieces'....
(X _ _ )(2X _ _ )
Now let's look at the '-12'....
This means that the two numbers could be....
1 and 12
2 and 6
3 and 4
And one number is + and the other is -
Since the middle term of the Quadratic is "5X", we need to 'play around' a bit with the possibilities....
1 and 12 are too far 'apart'
2 and 6 are both even, so we won't end up with 5X (since 5 is odd)
That just leaves us with 3 and 4....
(X + 4)(2X - 3) = 0
Now we can solve the Quadratic...
X = -4, +3/2
The prompt asks for the difference in the solutions...
(3/2) - (-4) = 11/2
Final Answer:
GMAT assassins aren't born, they're made,
Rich
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