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Maths help please

15 replies

bendmeoverbackwards · 09/03/2022 23:06

Inequalities - I can do these usually but this has x on 2 of the 3 sides!

Maths help please
OP posts:
TheGirlWhoLived · 09/03/2022 23:11

Think x is 1?

bendmeoverbackwards · 09/03/2022 23:13

No, the answer should be x is between 2 numbers. Just can’t work it out if x is on more than one side.

OP posts:
TheGirlWhoLived · 09/03/2022 23:14

-3 < 9 _< 9
-9 < 3 _< 3

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TheGirlWhoLived · 09/03/2022 23:16

Nah I’m out then, sorry! The only value I can see in both equations is x being 1. So the 3x works in both cases

Artimis · 09/03/2022 23:25

The maximum value for x is 3x+6 doesn't hold) Simplify by adding 4 to each side to get x > 3x + 10, then subtracting x to get 0 < 2x

Artimis · 09/03/2022 23:29

Oops correction

The maximum value for x is 3x+6 doesn't hold) Simplify by subtracting 4 from each side to get x -10 > 3x then subtracting x to get -10 < 2x

-5> x >= 1

Smidge001 · 09/03/2022 23:30

Between -5 and +1

Barleysugar85 · 09/03/2022 23:30

The equations work when x = 1, x =0 and x=-1, doesn't work for x = 2

I haven't carried on with the negative numbers to find the bottom limit though, it's worth just plugging in -2, -3 etc for x until you find at what number the equations stop being true

Artimis · 09/03/2022 23:31

Gah, subtract 6, not 4!

JenniferBarkley · 09/03/2022 23:34

Your second line is fine.

Then split out the inequalities.

So:

x - 10 < 3x meaning -10 < 2x and -5 < X

And

3x

FormerBoardingSchoolTeacher · 09/03/2022 23:42

Don’t try to do it all at once.

Maths help please
bendmeoverbackwards · 09/03/2022 23:56

Brilliant thank you all

OP posts:
DropYourSword · 10/03/2022 02:41

I think the answer is x is between -4 to 1.

If you plug in -5 for x then you get

-9 / -9 / 9 as your answers (which I think then shows -5 ISNT correct because -9 isn't < -9!)

RichTeaRichTea · 10/03/2022 02:56

@DropYourSword

I think the answer is x is between -4 to 1.

If you plug in -5 for x then you get

-9 / -9 / 9 as your answers (which I think then shows -5 ISNT correct because -9 isn't < -9!)

-5 < x

Means that x is always greater than -5 and not equal to it, so your calculation when using x = -5 shows that x < -5 is correct, as x=-5 doesn’t work. x might not be an integer, it could lie between -5 and -4

RichTeaRichTea · 10/03/2022 02:58

Sorry -5

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