mgmat absolute values

I feel it can't be answered by both the options ! the option should be E !


Thanks
Senthil

I am getting x=0 or x=2 from both the equations should be E

If I remember correctly this is a question from MGMAT, and they have a really good explanation for the solution. What did you not understand from the MGMAT explanation?

Well a very tricky question ..but indeed the answer is A.

Here is how - I learnt from some website that the best way to solve the mod problems is to remove the mod ...i.e. square the equation

so from both 1 and 2 we get the roots as 0 and 2. But if we put these values back in the given equations we see that both 0 and 2 satisfy equation 2 but only 2 satisfies equation 1... hence A is the answer

Simplyjat,

As you see, I am trying to see where I went wrong my esteemed and dear friend. Your memory serves you correctly and yes this is an mgmat question. The explanation is good but I do want to learn more about absolute values. I tend to get these wrong. This is why! ALso, I am aiming at enriching the conversation on absolute values here. If you don't like the topic, simply don't participate for you are here only on your own choice and voluntary basis.

Good point mandy,

Need to be careful with abs questions. I remember now that we need to always substitute back and confirm the roots work.

YES,

For abs I know that you must account for pos and neg situations but I was never checking the alues into the equation to confirm. THis was why I got it wrong. I learned something very important today!

go through this and you will discover the ancient lost art of solving absolute value equations.....
https://www.manhattangmat.com/strategy-s ... -value.cfm

There is another way to solve A

|x + 3| = 4x – 3
x = (|x + 3| + 3) / 4

which will always be +ve

nice approach i like that. makes sense too

Mandy12 - when do you find it appropriate (and easiest) to find the answer by squaring the equation. I had not thought about this approach before but am intrigued for it applications.