p1 …. p2

—- = ——

t1 ……t2

cross multiplying… you get…

p2 * t1 = p1 * t2

now divide both sides by “t1″…. and you get

p2 * t1 ….. p1 * t2

——— = ————

…t1 ………….t1

on the left side, the t1’s cancel…. leaving you with…

p2 = (p1 * t2) / t1

So far we haven’t done anything physics-related…. this was just plain algebra…. It’s a physic formula, but you are using your algebraic math skills to manipulate the formula so that you have “what you want to find” on the left…. and then the elements that you are going to use to calculate p2 are on the right side…

2. pv = nrt

Okay… we want to solve for “r” now…

Well…

Another way of writing pv = nrt, is nrt = pv, right?

Because pv and nrt are equivalent to each other… it doesn’t really matter if you write it…

pv = nrt…. or nrt = pv…. but because we are solving for “r”… I wanted it to be on the left side…

so….

pv = nrt…. became… nrt = pv….

Now how do you get “r” alone on the left side? Do you know?

Well, to get “r” alone… we divide BOTH sides by “nt”… like this…

nrt …. pv

—- = ——

nt …….nt

So that… the n’s and t’s cancel on the left leaving you with “r”…. and so you have…

r = (pv) / (nt)

DONE!!!! :o)

1. p1/t1 = p2/t2 —> mutiply both sides by t2, so the right side cancels out.

p1*p2 / t1 = p2

2. pv = nrt –>divide everything except for the r on the right side, so you can isolate the r.

r = pv/nt

2. Once again you want to have r = something. So looking at the side with r on it, you see that you want to move the n and the t over. So, you are multiplying r by n and t, so you will have to divide to undo the multiplication. (pv)/(nt) = r.

(p1/t1)(t2)= p2

pv = nrt divide out nt on each side to get r by itself

pv/(nt) = r