Rearranging Formulae Watch

SBizzy
Badges: 9
Rep:
?
#1
Report Thread starter 1 year ago
#1
I don't really understand how to rearrange formula e,our teacher taught the method when you put arrow then do it the other way again.

Question, If p=5L change the subject of the formula to L. Hence find L when P=73
0
quote
reply
Pangol
Badges: 12
Rep:
?
#2
Report 1 year ago
#2
(Original post by SBizzy)
I don't really understand how to rearrange formula e,our teacher taught the method when you put arrow then do it the other way again.

Question, If p+5L change the subject of the formula to L. Hence find L when P=73
There must be a little more to the question. p + 5L isn't an equation - it must be equal to something. Or do you mean p = 5L?
0
quote
reply
SBizzy
Badges: 9
Rep:
?
#3
Report Thread starter 1 year ago
#3
(Original post by Pangol)
There must be a little more to the question. p + 5L isn't an equation - it must be equal to something. Or do you mean p = 5L?
Yeah, p=5L my bad. Sorry.
0
quote
reply
Pangol
Badges: 12
Rep:
?
#4
Report 1 year ago
#4
(Original post by SBizzy)
Yeah, p=5L my bad. Sorry.
If p = 5L, then you find the value of p by multiplying L by 5. Think of L as the price of a light bulb, and p as the total cost of five of them. If you know the price of one light bulb (L), you can work out the total price by multiplying by 5. But suppose you knew the total price (p) - suppose this is £10. How much would each 5 of the light bulbs cost? How have you worked this out?

(I know it would be very easy to just give you the answer to your original question, but if you can follow this through, you should be able to do the same thing again and again in other questions.)
1
quote
reply
SBizzy
Badges: 9
Rep:
?
#5
Report Thread starter 1 year ago
#5
(Original post by Pangol)
If p = 5L, then you find the value of p by multiplying L by 5. Think of L as the price of a light bulb, and p as the total cost of five of them. If you know the price of one light bulb (L), you can work out the total price by multiplying by 5. But suppose you knew the total price (p) - suppose this is £10. How much would each 5 of the light bulbs cost? How have you worked this out?

(I know it would be very easy to just give you the answer to your original question, but if you can follow this through, you should be able to do the same thing again and again in other questions.)
Would it be £2 each?
0
quote
reply
Pangol
Badges: 12
Rep:
?
#6
Report 1 year ago
#6
(Original post by SBizzy)
Would it be £2 each?
Yes - and now you can see that you have to divide by 5, which is the opposite to multiplying by 5.

If you want to do this with algebra, the golden rule is to always do exactly the same thing to both sides of the equation. In this case, that thing is "divide by 5". So, we go from p = 5L to p/5 = 5L/5. and of course, if we take L, multiply by 5 to get 5L, and then divide by 5 again, we get right back where we started, so 5L/5 = L, and you end up with L = p/5.
0
quote
reply
SBizzy
Badges: 9
Rep:
?
#7
Report Thread starter 1 year ago
#7
(Original post by Pangol)
Yes - and now you can see that you have to divide by 5, which is the opposite to multiplying by 5.

If you want to do this with algebra, the golden rule is to always do exactly the same thing to both sides of the equation. In this case, that thing is "divide by 5". So, we go from p = 5L to p/5 = 5L/5. and of course, if we take L, multiply by 5 to get 5L, and then divide by 5 again, we get right back where we started, so 5L/5 = L, and you end up with L = p/5.
Still struggling with this homework...
0
quote
reply
Pangol
Badges: 12
Rep:
?
#8
Report 1 year ago
#8
(Original post by SBizzy)
Still struggling with this homework...
Not easy to know what to say considering the only question you have posted has been answered...
0
quote
reply
SBizzy
Badges: 9
Rep:
?
#9
Report Thread starter 1 year ago
#9
(Original post by Pangol)
Not easy to know what to say considering the

only question you have posted has been answered...
I'll just stop doing it, thanks for your help!
0
quote
reply
X

Reply to thread

Attached files
Write a reply...
Reply
new posts
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

University open days

  • Sheffield Hallam University
    City Campus Undergraduate
    Thu, 13 Dec '18
  • University of Buckingham
    Open Evening Undergraduate
    Thu, 13 Dec '18
  • University of Lincoln
    Mini Open Day at the Brayford Campus Undergraduate
    Wed, 19 Dec '18

Do you like exams?

Yes (206)
18.61%
No (673)
60.79%
Not really bothered about them (228)
20.6%

Watched Threads

View All