How to rearrange to make D the subject?

Hi,

For some reason i'm struggling to rearrange a lot of equations where i'm attempting to make a variable that appears twice in the equation the subject. At the moment i am attempting to rearrange this equation to make D the subject. May someone please show me how to do this in steps please?

And if possible, i would like some tips on how to make variables that appear twice the subject please?

Any help is much appreciated

Rob

Re: How to rearrange to make D the subject?

You have

A good first step would be to multiply by the denominator to get

Expand the brackets

Rearrange a little

factorise, and I'll leave the rest to you.

Re: How to rearrange to make D the subject?

Hello, Rob!

Since there is a in the denominator, multiply by

. .

Get all -terms on one side, the rest on the other side.

. .

Factor out the

, .

Solve for . . . divide by

. .

~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~

This answer is correct,

. . but you may see it in a different form.

Multiply the fraction by

. .

Re: How to rearrange to make D the subject?

Quote:

Originally Posted by

**a tutor**
factorise, and I'll leave the rest to you.

I managed to get it up to this point but for some reason i just couldn't think about how to do the next step. It was just so simple. I kind of kick myself for not being able to figure it out. lol :)

Much appreciated to you both.