Question

In the formula A=bh, of b is tripled and h is quadrupled, then A is multiplied by N. Compute N.

Answer 1

@phi

Answer 2

@SithsAndGiggles

Answer 3

So you have
AN=(3b)(4h)
Then simplify the right side
And then divide both sides by A
So now you have N=...

Answer 4

How do you simplify the right side?

Answer 5

@nikato

Answer 6

when you multiply numbers (or letters) you can change the order
so, for example,
(3b)(4h)= 3*4*b*h

most people know how to simplify the 3*4 part

Answer 7

So 3*4=12
Now is it 12*b*h?

Answer 8

yes, exactly. But in algebra we don't write the multiply signs... just write 12bh
(which means 12 times b times h)

Answer 9

Okay. Now what do I do?

Answer 10

you have
AN= 12 bh

they want N "by itself"
I would divide both sides by A

Answer 11

But how do I do that?

Answer 12

when you do arithmetic with letters, you just write down "divide by A"
for example
AN/A = 12bh/A
or
\[ \frac{AN}{A}= \frac{12bh}{A} \]

Answer 13

next you use a very useful idea: *anything divided by itself is 1"

in other words A*N/A (also written as A/A * N )
becomes
1*N

and 1 times N is N
you get

N= 12bh/A

Answer 14

Thanks :)

Answer 15

It would be good to go over that and see if it "sinks in". Math uses these ideas *all the time* and you really should try to learn it.