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Re: If a+b=ab, then a*b must be equal to:
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05 Jan 2015, 05:49
I am not sure if the way I thought of the absolute value was correct, but here it is.
QUESTION: If a+b=ab, then a*b must be equal to:
I thought that when there is an absolute value, we think of the "value" within it with no regards to the sign. So, I thought it could be: a+b= ab. If we move a to the other side, both a's get cancelled, which leads to b=b. Moving b to the other side it becomes 2b=0. So, b=0, which means that a*b must be equal to 0.



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Re: If a+b=ab, then a*b must be equal to:
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05 Jan 2015, 06:07
pacifist85 wrote: I am not sure if the way I thought of the absolute value was correct, but here it is.
QUESTION: If a+b=ab, then a*b must be equal to:
I thought that when there is an absolute value, we think of the "value" within it with no regards to the sign. So, I thought it could be: a+b= ab. If we move a to the other side, both a's get cancelled, which leads to b=b. Moving b to the other side it becomes 2b=0. So, b=0, which means that a*b must be equal to 0. You are missing the second case there. If a+b and ab have the same sign, then we'd have a+b = ab > b=0 > ab=0; If a+b and ab have the opposite signs, then we'd have a+b = (ab) > a=0 > ab=0.
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Re: If a+b=ab, then a*b must be equal to:
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05 Jan 2015, 06:39
Thank you for explaining. I have gone through the absolute values, but they keep creating some confusion.



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Re: If a+b=ab, then a*b must be equal to:
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27 Mar 2018, 07:08
Quote: If a+b=ab, then a*b must be equal to:
A. 1 B. 1 C. 0 D. 2 E. 2 niks18 Bunuel chetan2u pushpitkcLet me know if below approach is correct: a+b or ab will always yield a positive value. This is because a modulus always represents an ABSOLUTE distance from number line.So a+b=ab simplifies to a + b = a  b I can cancel a from both sides in all circumstances.2b = 0 > b = 0 or a*b = 0 Hope assumptions made by me are correct.
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If a+b=ab, then a*b must be equal to:
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27 Mar 2018, 07:40
adkikani wrote: Quote: If a+b=ab, then a*b must be equal to:
A. 1 B. 1 C. 0 D. 2 E. 2 niks18 Bunuel chetan2u pushpitkcLet me know if below approach is correct: a+b or ab will always yield a positive value. This is because a modulus always represents an ABSOLUTE distance from number line.So a+b=ab simplifies to a + b = a  b I can cancel a from both sides in all circumstances.2b = 0 > b = 0 or a*b = 0 Hope assumptions made by me are correct. Ans here will be either A or B or both are 0.. And this is why.. You cannot remove modulus this way, you do know if B is greater or A or they are NEGATIVE.. So square both sides, since both are modulus.. a^2+b^2+2ab=a^2+b^22ab..... 4ab=0.. So either A or B or both are 0
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1) Absolute modulus : http://gmatclub.com/forum/absolutemodulusabetterunderstanding210849.html#p1622372 2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html 3) effects of arithmetic operations : https://gmatclub.com/forum/effectsofarithmeticoperationsonfractions269413.html
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Re: If a+b=ab, then a*b must be equal to:
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27 Mar 2018, 07:46
chetan2u Quote: You cannot remove modulus this way, you do know if B is greater or A or they are NEGATIVE. But we shall still always get END RESULT as positive on opening modulus. 5 = 5  5 =  (5) = 5 Am I correct?
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Re: If a+b=ab, then a*b must be equal to:
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27 Mar 2018, 08:13
adkikani wrote: chetan2u Quote: You cannot remove modulus this way, you do know if B is greater or A or they are NEGATIVE. But we shall still always get END RESULT as positive on opening modulus. 5 = 5  5 =  (5) = 5 Am I correct? Yes you are correct.. But 53=35 does not mean 53=35... That is 2=2?? So square the MODULUS to get rid of Modulus
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1) Absolute modulus : http://gmatclub.com/forum/absolutemodulusabetterunderstanding210849.html#p1622372 2)Combination of similar and dissimilar things : http://gmatclub.com/forum/topic215915.html 3) effects of arithmetic operations : https://gmatclub.com/forum/effectsofarithmeticoperationsonfractions269413.html
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Re: If a+b=ab, then a*b must be equal to: &nbs
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27 Mar 2018, 08:13



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