Need Help With Algebra Question

#1
Hope someone here can help me with this. Basically I'm joining in October to be an AET so I'm brushing up on my maths skills. At the moment I'm doing algebra and I'm stuck on this question; 5-(x-3)=10-3x . What I have to do is find the value of x which would be really easy if it wasn't for the minus sign in front of the bracket which is throwing me off. How are you supposed to deal with it?
 

OSLO

War Hero
#2
I'll assume this isn't a piss take:

First, you need to simplify the left hand side (LHS). The "-" in front of the (x-3) part means that when you remove the brackets, the signs in the brackets change:
-(x-3) => -x --3

Now, a "--" is a "+".

So we have 5-x+3 = 10-3x or 8-x = 10-3x

Now we need to bring all "x" onto one side, and numbers on the other. It doesn't matter which one goes to which side. Let's use move the "-3x" part by adding "3x" to both sides:

8-x +3x = 10 -3x +3x

<=> (this means both equations are the same)

8+2x =10

Now subtract 8 from both sides:

8+2x-8 = 10-8

<=>

2x = 2

Divide by 2:

2x/2 = 2/2

<=>

x=1

Now check by replacing "x=1" into the original equation:

5 - (1-3) = 10 - 3

<=>

5--2 = 7

<=>

7=7

So your answer is x=1, and I hope you can now do this for any similar equation.

PS. If this is a piss take, f*** off!
 
#3
PS. If this is a piss take, f*** off!
lol, this isn't a piss take. I haven't done algebra in four years so I'm trying to brush up my skills before I start training. I'm working through a GCSE algebra book at the minute which I should have finished by the end of the month, and then I have an AS/A level one to work on next month. I'm working on it daily so I should progress quickly. It's just a matter of re-learing what I've forgotten.

Now that you show how it's done it seems so obviously simple :thanks: . Cheers!
 

toycommandos

Lantern Swinger
#7
OSLO said:
I'll assume this isn't a piss take:

First, you need to simplify the left hand side (LHS). The "-" in front of the (x-3) part means that when you remove the brackets, the signs in the brackets change:
-(x-3) => -x --3

Now, a "--" is a "+".

So we have 5-x+3 = 10-3x or 8-x = 10-3x

Now we need to bring all "x" onto one side, and numbers on the other. It doesn't matter which one goes to which side. Let's use move the "-3x" part by adding "3x" to both sides:

8-x +3x = 10 -3x +3x

<=> (this means both equations are the same)

8+2x =10

Now subtract 8 from both sides:

8+2x-8 = 10-8

<=>

2x = 2

Divide by 2:

2x/2 = 2/2

<=>

x=1

Now check by replacing "x=1" into the original equation:

5 - (1-3) = 10 - 3

<=>

5--2 = 7

<=>

7=7

So your answer is x=1, and I hope you can now do this for any similar equation.

PS. If this is a piss take, f*** off!


Why do 2 "-" = a "+" ????
Thats the only bit that confused me.
 

OSLO

War Hero
#8
There are many ways to explain it, but here's one I remember as being more tangible:

Say you're driving along a country road at 60mph. You come to a sign saying that the speed limit is 40mph, so you "remove" 20mph from you speed (i.e. 60 - 20 = 40).

You come to end of the 40mph zone and the speed limit goes back to the national speed limit, single carriageway, i.e. 60 mph. You increase speed, thus "removing" the "-20" that you imposed earlier, i.e.
-20 - (-20) = -20 + 20 = 0.

Does that make sense?

If you want a more "mathsy" answer, consider the equation -5 -(-3):

-5 = -1 x 5 (i.e. -1 times 5)
-3 = -1 x 3

So we have
-5 - (-3) = (-1 x 5) - (-1 x 3)

Take the "-1" out of the equation:

(-1 x 5) - (-1 x 3) = -1 x (5 - 3) = -1 x (2) = -2

So -5 - (-3) = -2

It's not the easiest of concepts to grasp, but it is a fundamental one.
 
#12
Helios said:
Hope someone here can help me with this. Basically I'm joining in October to be an AET so I'm brushing up on my maths skills. At the moment I'm doing algebra and I'm stuck on this question; 5-(x-3)=10-3x . What I have to do is find the value of x which would be really easy if it wasn't for the minus sign in front of the bracket which is throwing me off. How are you supposed to deal with it?
So what age are you that you didn't learn this simple algabraic equation at school? Perhaps it's nothing to do with your age ( or ability), but that your school is/was at fault. What school is/was it?
 

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