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Mathematics 62 Online
OpenStudy (meehan98):

Need Help checking my answer, please!

OpenStudy (alexandervonhumboldt2):

yeah

OpenStudy (alexandervonhumboldt2):

i'm here

OpenStudy (meehan98):

\[\left| 2x1 \right|\le 11\]

OpenStudy (alexandervonhumboldt2):

what does 1 after x means?

OpenStudy (meehan98):

I got: \[x \le 5 or x \ge 5\]

OpenStudy (meehan98):

Sorry..(2x+1)

OpenStudy (alexandervonhumboldt2):

oh

OpenStudy (mathstudent55):

When solving an absolute inequality of this type, you need to change the absolute value inequality into a compound inequality (without absolute value signs.)

OpenStudy (meehan98):

So, 2x+1=11 which would make x=5

OpenStudy (mathstudent55):

\(|X|\le k\) Here, X stands for an expression in x, and k is a non-negative number. Solve this compound inequality: \(-k \le X \le k\)

OpenStudy (mathstudent55):

N ow we look at your absolute value inequality. \(|2x + 1| \le 11\) It becomes: \(-11 \le 2x + 1 \le 11\) Now we solve the compound inequality. Subtract 1 from all 3 sides: \(-12 \le 2x \le 10\) Divide all 3 sides by 2: \(-6 \le x \le 5\) Which means the same as \(x \ge -6\) and \(x \le 5\)

OpenStudy (meehan98):

Oh, thank you! That helps so much!

OpenStudy (mathstudent55):

You're welcome. If the absolute value inequality has a \(\gt\) or a \(\ge\), then this is what you do: \(|X| \gt k\) becomes \(X \lt -k\) or \(X \gt k\) In this case, the compound inequality has the word "or" instead of "and".

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