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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE Mathematical Methods CAS => Topic started by: Rose34 on February 27, 2020, 09:43:04 pm

Title: Math methods units 1&2
Post by: Rose34 on February 27, 2020, 09:43:04 pm: Solve for the following inequality with graphing
6x^2+ 13x <−6
Title: Re: Math methods units 1&2
Post by: PhoenixxFire on February 28, 2020, 11:43:51 am: Hey,
What specifically are you stuck on? Us just giving you the answer won't really help to improve your understanding but if you post your working out or the thought process you've gone through attempting to answer this yourself then we'll be able to see what part is causing you trouble so that you can work it out yourself the next time you come across a question like this.
Title: Re: Math methods units 1&2
Post by: Rose34 on February 28, 2020, 04:02:33 pm: Quote from: PhoenixxFire on February 28, 2020, 11:43:51 am
Hey,
What specifically are you stuck on? Us just giving you the answer won't really help to improve your understanding but if you post your working out or the thought process you've gone through attempting to answer this yourself then we'll be able to see what part is causing you trouble so that you can work it out yourself the next time you come across a question like this.

I apologize for not doing that, I am new to this website so I did not really know how it works.

To be honest I know how to find the values for x, but what I do not understand is that how are we supposed to write the inequality for example, is it supposed to be -3/2<x or -3/2>x. That is what is confusing me when are we supposed to switch the sign?.

I hope that makes sense now
Title: Re: Math methods units 1&2
Post by: Sine on February 28, 2020, 04:04:45 pm: Quote from: Rose34 on February 28, 2020, 04:02:33 pm
I apologize for not doing that, I am new to this website so I did not really know how it works.

To be honest I know how to find the values for x, but what I do not understand is that how are we supposed to write the inequality for example, is it supposed to be -3/2<x or -3/2>x. That is what is confusing me when are we supposed to switch the sign?.

I hope that makes sense now
With quadratics, I think the best way is to graph it out and just work it out from there. It can get confusing changing inequalities when you have negatives/square rooting both sides etc
Title: Re: Math methods units 1&2
Post by: BiggestVCESweat on February 29, 2020, 11:15:18 am: Quote from: Sine on February 28, 2020, 04:04:45 pm
With quadratics, I think the best way is to graph it out and just work it out from there. It can get confusing changing inequalities when you have negatives/square rooting both sides etc
Nah, I find that takes too long and uses too much space.
Personally I would just solve for x and know that since it is a positive quadratic the values in between the x-intercepts will be under 0.
Title: Re: Math methods units 1&2
Post by: Rose34 on March 03, 2020, 07:51:08 am: Thank you all for the help!
Title: Re: Math methods units 1&2
Post by: Bri MT on March 03, 2020, 09:00:47 am: Quote from: BiggestVCESweat on February 29, 2020, 11:15:18 am
Nah, I find that takes too long and uses too much space.
Personally I would just solve for x and know that since it is a positive quadratic the values in between the x-intercepts will be under 0.

Since it's not always that region depending on the quadratic (as you've identified) and the inequality often students get confused doing it in their heads. If that works for you, great! Do whatever works best for you, but I find that a rough/quick sketch (not making a full proper graph) doesn't take long & is the safe way to go for most students.