Absolute Value: Solve for x | MHB

In summary, The conversation discusses solving the equation ||x|-2|+|x+1|=3 and finding the values of x. The solutions are x=0,-2,2,-1. The speaker mentions checking different cases such as x<-2, -2<x<-1, etc. in order to find the correct solution. They also mention that |x+1| behaves strangely at x=-1. Finally, the speaker thanks the expert for their help in finding the correct solution.
  • #1
Petrus
702
0
Hello MHB,
solve \(\displaystyle ||x|-2|+|x+1|=3\)
and we find that \(\displaystyle x=0,-2,2,-1\)
I got problem to find the 'case',

Regards,
\(\displaystyle |\rangle\)
 
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  • #2
Petrus said:
Hello MHB,
solve \(\displaystyle ||x|-2|+|x+1|=3\)
and we find that \(\displaystyle x=0,-2,2,-1\)
I got problem to find the 'case',

Regards,
\(\displaystyle |\rangle\)

That doesn't look like the right solution...

Talking about cases, what if x<-2? Or -2<x<-1? And what about -1<x<0? Or perhaps 0<x<2? And x>2?
 
  • #3
I like Serena said:
That doesn't look like the right solution...

Talking about cases, what if x<-2? Or -2<x<-1? And what about -1<x<0? Or perhaps 0<x<2? And x>2?
I don't mean those are the answer, but those are the point we should check \(\displaystyle \geq\) or \(\displaystyle \leq\), I hope you did understand.
Can I also check this one insted of -1<x<0
-2<x<0?

Regards,
\(\displaystyle |\rangle\)
 
  • #4
Petrus said:
I don't mean those are the answer, but those are the point we should check \(\displaystyle \geq\) or \(\displaystyle \leq\), I hope you did understand.
Can I also check this one insted of -1<x<0
-2<x<0?

Sure you can. It's just that |x+1| does something funny at x=-1.
 
  • #5
I like Serena said:
Sure you can. It's just that |x+1| does something funny at x=-1.
Thanks, got the correct answer now :)
Regards,
\(\displaystyle |\rangle\)
 

FAQ: Absolute Value: Solve for x | MHB

What is absolute value?

Absolute value is a mathematical concept that represents the distance of a number from zero on a number line. It is always a positive value and is denoted by the symbol "|" before and after the number.

How do you solve for x in an absolute value equation?

To solve for x in an absolute value equation, you need to isolate the absolute value expression on one side of the equation. Then, remove the absolute value bars and create two equations, one with a positive value and one with a negative value. Solve for x in both equations and you will have two solutions for x.

What are the properties of absolute value?

The properties of absolute value are:

  • Absolute value is always a positive value.
  • The absolute value of zero is zero.
  • The absolute value of a negative number is the same as the positive number without the negative sign.
  • The absolute value of a positive number is the same as the number itself.
  • The absolute value of a sum of two numbers is equal to the sum of their absolute values.

What are some common mistakes when solving absolute value equations?

Some common mistakes when solving absolute value equations include:

  • Forgetting to create two equations, one with a positive value and one with a negative value, after removing the absolute value bars.
  • Mistakes in simplifying the expressions within the absolute value bars.
  • Forgetting to check the solutions in the original equation to ensure they are valid.
  • Confusing the order of operations when solving an equation with multiple absolute value expressions.

How is absolute value used in real life?

Absolute value is used in various real-life situations, such as calculating distances, measuring errors, determining the magnitude of a force, and finding the difference between two values. It is also used in fields such as physics, engineering, and statistics to represent and analyze data. In everyday life, absolute value can be seen in temperature changes, bank account balances, and sports statistics.

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