Applying to University? Check out our Applicant Thread Directory!

Your year in review, check out TSR Rewind

Applying to University? Check out our Applicant Thread Directory!

Your year in review, check out TSR Rewind

Make b the subject of the formula - please help, not long!

I'm normally good at these, but I'm tired and my brain is just not working:

Make b the subject of the formula.
a = 2-7b over b-5

No brackets.

Thank you. :smile:

:smile:

Thing to do is get all the terms you want the subject to be on one side, so in this case B.

Multiply both sides by the denominator b-5 and then move all B's to one side and factorise

jumblebumble

I'm normally good at these, but I'm tired and my brain is just not working:

Make b the subject of the formula.
a = 2-7b over b-5

No brackets.

Thank you. :smile:

:smile:

\displaystyle a = \frac{2-7b}{b-5}

First multiply by the underside of the fraction

\displaystyle a (b-5 ) = 2 - 7b

Then expand the brackets, and collect all b terms on one side of the equation

\displaystyle ab - 5a + 7b = 2

Collect all non-b terms on the right hand side, and factorise the left hand side

\displaystyle b ( a + 7) = 2 + 5a

And divide through by the factor of b

\displaystyle b = \frac{5a + 2}{a + 7}

Done.

OP

Thank you very much - it was the last question of my paper, which is now done. :wink:

:wink:

Get all the b's to one side to begin with so....a(b-5)=2-7b
>> ab+7b=2+5a.....try from there :smile:

:smile:

.....(putting in brackets might help :smile:

:smile:

OP

timotiis

\displaystyle a = \frac{2-7b}{b-5}

Then expand the brackets, and collect all b terms on one side of the equation

\displaystyle ab - 5b + 7b = 2

Done.

Sorry to be a pain, but where has the 5a gone?

x

jumblebumble

Sorry to be a pain, but where has the 5a gone?

x

Thank you, my mistake. I'll just go edit that...

OP

Thank you. :smile:

:smile:

jumblebumble

Thank you. :smile:

:smile:

No problem. Slightly shameful really, I should know better than to make that sort of error.

OP

Haha. Well you did better than me - i managed all the histograms, circle theorems, sine graph translations...just not this! :biggrin:

:biggrin:

Where did you get the add 7b from?

Latest

Trending

Articles for you

What is an EPQ and why might you want to do one?

What is an EPQ and why might you want to do one?

How to write your law personal statement...and make it really stand out

How to write your law personal statement...and make it really stand out

Can you speak lawyer?

Can you speak lawyer?

Discussion time: what laws protect women’s rights in the UK?

Discussion time: what laws protect women’s rights in the UK?

Try out the app

Continue on web