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Mathematics 12 Online
OpenStudy (dtan5457):

Absolute value inequality check

OpenStudy (dtan5457):

\[\left| x^2-2x \right|=3x-6\]

OpenStudy (dtan5457):

I got +/-3,2

OpenStudy (alexandervonhumboldt2):

ok so x^2-2x=3x-6 x^2-2x=-3x+6

OpenStudy (dtan5457):

so i made them quadratics and got +/-3,2 am i correct?

OpenStudy (alexandervonhumboldt2):

hmm i think so

OpenStudy (dtan5457):

is 2 extraneous by any chance?

OpenStudy (dtan5457):

or does it not matter if 0=0?

OpenStudy (alexandervonhumboldt2):

no

OpenStudy (alexandervonhumboldt2):

0=0 so non-extraneus

OpenStudy (dtan5457):

extraneous is just when the values don't equal each other right?

OpenStudy (unklerhaukus):

\[|x^2-2x|=3x-6\] To check you solutions, plug them into the original equation The first solution you got was x=3 \[|(3)^2-2(3)|=3(3)-6\\ |9-6|=9-6\\ |3|=3\\ 3=3\] Which is always true, so x=3 is a solution. The second solution you got was x=-3 \[|(-3)^2-2(-3)|=3(-3)-6\\ |9+6|=-9-6\\ |15|=-15\\ 15=-15\] Which is never true, so x=-3 is not a solution (check your working) The third solution you got was x=2 \[|(2)^2-2(2)|=3(2)-6\\ |4-4|=6-6\\|0|=0\\ 0=0\] Which is always true so x=2 is a solution.

OpenStudy (dtan5457):

Oh, i see

OpenStudy (unklerhaukus):

Is the equation meant to be an in-equation?

OpenStudy (dtan5457):

not sure what that means

OpenStudy (unklerhaukus):

The question in the original post says "Absolute value INEQUALITY check" an inequality has an inequality sign (such as \(<,>\leq,\geq\)) whereas; a equation has an equality sign \(=\)

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