Uploaded by vividmaths on 14.03.2012

Transcript:

Ok, guys here’s our chance to do a really challenging question. What we are going to

do here is make “a” the subject of this formula. At the present moment as you can

see “b” is the subject so how we make “a” the subject particularly when there

are two “a’s” on top here of “a” minus three (a-3) and again “a” minus

four (a-4) as the denominator.

So the first thing we have to do is multiply both sides by “a” minus four (a-4) or

if you want to think of it as cross multiplying that corner times that corner it’s still

the same process. So let’s multiply both sides by “a” minus four (a-4). “a”

minus four (a-4) and times “a” minus four (x a-4). Ok that will give here “b” outside

of a minus four equals (b (a-4=) and if we cancel this two guys, “a” minus four (a-4)

“a” minus four (a-4) which is simply left a minus three (a-3). Ok, let’s expand the

left hand side, so we have “b & a” minus four b equals "a" minus three (ba-4b=a-3).

Now what are we looking for, we are looking for getting the “a’s” together so what

I’m going to do is draw the 4b over the outside and “a” over this side. So, the

four b (+ 4b) will go to plus four b (+ 4b) and plus four b (+4b) here and at the same

time we are going to take away “a” and take away “a”, all right that’s an idea.

Alright, let’s do that now, so what we have here is “ba” minus “a” equals four

“b” minus three (ba-a=4b-3). Ok, let’s factor on the left hand side so we can make

“a” subject and we can take “a” out so it’s “a” bracket “b” minus one

equals four “b” minus three: a(b-1) = 4b-3. Ok, let’s divide both sides by “b” minus

one (b-1) and that will make this “a” the subject which is the outcome of this exercise

so let’s divide both sides by “b” minus one (b-1) so we'll divide it by “b” minus

one and “b” minus one (b-1) and if we write it up here it will become “a” equals;

and on the top we have four “b” minus three (4b-3)– all over and the “b” minus

one (b-1) over here and that is here is our answer: a is the subject.

Take a minute to check out in our website at http://www.vividmaths.com. You will find

additional resources, cheat sheets, transcripts and other mass videos that are not available

in Youtube. Lastly, don’t forget to subscribe to get access to all ready answer for all

your math questions plus other special offers.

do here is make “a” the subject of this formula. At the present moment as you can

see “b” is the subject so how we make “a” the subject particularly when there

are two “a’s” on top here of “a” minus three (a-3) and again “a” minus

four (a-4) as the denominator.

So the first thing we have to do is multiply both sides by “a” minus four (a-4) or

if you want to think of it as cross multiplying that corner times that corner it’s still

the same process. So let’s multiply both sides by “a” minus four (a-4). “a”

minus four (a-4) and times “a” minus four (x a-4). Ok that will give here “b” outside

of a minus four equals (b (a-4=) and if we cancel this two guys, “a” minus four (a-4)

“a” minus four (a-4) which is simply left a minus three (a-3). Ok, let’s expand the

left hand side, so we have “b & a” minus four b equals "a" minus three (ba-4b=a-3).

Now what are we looking for, we are looking for getting the “a’s” together so what

I’m going to do is draw the 4b over the outside and “a” over this side. So, the

four b (+ 4b) will go to plus four b (+ 4b) and plus four b (+4b) here and at the same

time we are going to take away “a” and take away “a”, all right that’s an idea.

Alright, let’s do that now, so what we have here is “ba” minus “a” equals four

“b” minus three (ba-a=4b-3). Ok, let’s factor on the left hand side so we can make

“a” subject and we can take “a” out so it’s “a” bracket “b” minus one

equals four “b” minus three: a(b-1) = 4b-3. Ok, let’s divide both sides by “b” minus

one (b-1) and that will make this “a” the subject which is the outcome of this exercise

so let’s divide both sides by “b” minus one (b-1) so we'll divide it by “b” minus

one and “b” minus one (b-1) and if we write it up here it will become “a” equals;

and on the top we have four “b” minus three (4b-3)– all over and the “b” minus

one (b-1) over here and that is here is our answer: a is the subject.

Take a minute to check out in our website at http://www.vividmaths.com. You will find

additional resources, cheat sheets, transcripts and other mass videos that are not available

in Youtube. Lastly, don’t forget to subscribe to get access to all ready answer for all

your math questions plus other special offers.