Maths help

mattux · 19 Mar 2015 at 18:42

Hi

Not sure if correct forum to post in, please move if necessary.

I need some help with equations and unknowns please.
I have the following equation.

5x +2 = 2x -6 I think i should try and get the x on one side so take away 2x

3x +2 = -6 Then i think i should add 6 to get rid of the -6 but that would leave the equals sign with nothing to the right

3x +8 = 0 can I do this and then move the +8 across ( i am trying to avoid the negative numbers)

Or do i take away the +2 leaving
3x = -8

And then -8/3 ? Problem is I dont like negative numbers

This is to help my daughter with her math homework, its times like this I really wish I had paid attention in school

mattux · 19 Mar 2015 at 18:49

ikillbears said:
+s

Helpful thanks

mattux · 19 Mar 2015 at 18:50

AlecR said:
*Maths

3x = -8
x = -8/3

So yes you're right. You'll get a negative whatever you do as that is the solution to this equation.

Thanks Alec much appreciated

mattux · 19 Mar 2015 at 19:09

SO x = -8/3

I get x = -2.66666666667

Is this the correct answer and presentation?

mattux · 19 Mar 2015 at 19:12

muon said:
Leave it is a fraction.

So just x = -8/3

Thanks for the help muon

mattux · 19 Mar 2015 at 19:14

AlecR said:
You've lost accuracy there, much better to leave it as a fraction, i.e. -8/3.

I suppose you could say -x = 8/3 if you really hate negatives.

Or I suppose you could say |x| = 8/3

Thanks again Alec

really starting to find mathS fascinating.

mattux · 19 Mar 2015 at 19:31

Yes I understood what you were saying alec, you listened to my fear for negative numbers but they are not that bad at all actually as i have just discovered.

mattux · 19 Mar 2015 at 19:41

AlecR said:
Next stop, solve x^2 = -1.

X2 + 1 = 0 ??

the 2 should be little and on top but not sure how to do that

mattux · 19 Mar 2015 at 19:54

muon said:
What does x^2 mean?

It means x squared or x multiplied by itself.

1^2 = 1
2^2 = 4
3^2 = 9

etc.

So what multiplied by itself equals -1?

mattux · 19 Mar 2015 at 19:54

mattux · 19 Mar 2015 at 19:57

muon said:
What does x^2 mean?

It means x squared or x multiplied by itself.

They call it an exponent

10^8 would be 10x10x10x10x10x10x10x10 and not 10x8

mattux · 19 Mar 2015 at 19:59

muon said:
If you put -1 times -1 in a calculator you will get 1.

A negative number multiplied by a negative number is positive.

yes this is confusing me muon

same signs = positive

different signs = negative

mattux · 19 Mar 2015 at 20:01

PhysicsMan94 said:
(-1)*(-1) = 1

The actual answer to x^2 = -1 is x = +/- i where i is the imaginary number (i = sqrt(-1)). But don't worry about it, if you're daughter is only doing simple linear equations at the moment then complex numbers are quite a way off yet

Its her first secondary year, think they call it year 7 nowdays. I want to help as much as i can as i wasted too much of those years and do not want her to end up the same.

mattux · 19 Mar 2015 at 20:02

muon said:
The question has no real answer.

.

Ah that would be why I am so confused then