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Mathematics 16 Online
OpenStudy (anonymous):

What is the solution set of the absolute value sentence |x + 9| < 2?

OpenStudy (anonymous):

Two principles can help here: \[|a|^2=a^2\]and if\[a<b \text{ then }\]\[a^2<b^2 \text{ ; where }a,b>0\]

OpenStudy (anonymous):

ok when have | | < or > any number it will be come as: -2< x+9< 2 then u jst has 2 let x alone by give -9 to both side here it 'll be -11< x< -7 thts it up to ths kind of question

OpenStudy (anonymous):

now give me another ques if theres = insted of <

OpenStudy (moongazer):

| | sign means "absolute value" meaning the sign inside the | | doesn't matter, it will always be positive. for example; |-9|=9 |9|=9 and you can solve this inequality just like solving equations.

OpenStudy (moongazer):

x<-7

OpenStudy (anonymous):

The | | sign does matter for inequalities. Not all x < -7 work, take -100 for example: |-100+9|=|-91|=91. 91 is most definitely not less than 2.

OpenStudy (lalaly):

\[\large{-2<x+9<2}\]now subtract 9 from both sides\[-11<x<-7\]

OpenStudy (moongazer):

ohh I see, How did it become -2< x+9< 2 ??? I just want to know. :)

OpenStudy (anonymous):

there is rule that if where c should be positive

OpenStudy (anonymous):

-2<x+9<2 -11<x<-7*this is the answer

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