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Mathematics 25 Online
OpenStudy (anonymous):

Is the inequality below sometimes, always, or never true? -2(2x + 9) > -4x + 9 I want a simple explanation please. I'm having a lot of trouble with math and I need help understanding.

OpenStudy (misty1212):

HI!!

OpenStudy (anonymous):

Hello. I'm not asking for the answer because I know that's not allowed I just need someone to explain this to me.

OpenStudy (misty1212):

probably the best bet is to multiply out first on the left i.e. distribute the \(-2\)

OpenStudy (misty1212):

\[-2(2x + 9) > -4x + 9\\ -4x-18>-4x+9\]

OpenStudy (misty1212):

this is kind of a trick question, but lets keep going

OpenStudy (anonymous):

Trying to understand... The textbook hardly explains anything so I'm struggling

OpenStudy (misty1212):

this is kind of a trick question, but lets keep going

OpenStudy (anonymous):

Okay thanks. Explain it to me as easy as you can. Usually I will be able to understand when i analyze it a few times and really think about it

OpenStudy (misty1212):

do you see how i distributed the \(-2\) on the left hand side of the inequality?

OpenStudy (anonymous):

I think so. Did you multiply 9x2?

OpenStudy (misty1212):

actually \(-2\times 9\)

OpenStudy (anonymous):

Okay I'm starting to slowly get it now.

OpenStudy (misty1212):

now comes the tricky part

OpenStudy (anonymous):

I think it's always true because the last equation is.. true... am i getting this right?

OpenStudy (misty1212):

\[-4x-18>-4x+9\] \(x\) is a variable, so it can be anything but whatever it is on the left, it is the same thing on the right so the \(-4x\) on the left is equal to the \(-4x\) on the right

OpenStudy (misty1212):

adding \(4x\) to both sides gives \[-18>9\] which is NEVER true

OpenStudy (anonymous):

okay okay I'm starting to understand this. I think i got it now. Thank you so much :)

OpenStudy (misty1212):

\[\color\magenta\heartsuit\]

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