00:02
All right.
00:05
For this problem, we were dealing with 44 cents, 44 cent stamps, and 17 cents.
00:27
A person spent $14 .40 to purchase 45 of these stamps.
00:48
We can write this in a couple of ways, and i'm going to show you how to write it so that we can then get to working with an equation that only has one variable.
00:59
We're going to go ahead and say that x is 44 cents stamps and y is 17 cents stamps.
01:09
And so in our equations, we are going to say that we know that they bought some amount of 44 set stamps and some 17 cents stamps, and they bought a total of 45 stamps.
01:29
We want to work with x.
01:31
So the first thing we want to find is our x values.
01:35
So i'm going to go ahead and rewrite this equation so that i have y all by itself, so that when i write my final equation, you'll see what happens.
01:47
So this is the same as saying the number of 17 cents stamps is equal to.
01:52
To 45 minus x.
01:56
Okay.
01:57
The other way, the other part we want to focus on now is this $14 .40 to purchase the stamps.
02:04
We know that we have 44 cents stamps, so we would take 0 .44 and multiply it by x and then we have 0 .17 for the 17 cents stamps times y, and that's going to equal $14 .40.
02:26
But we don't want to work in an equation with x and y.
02:30
So that is where this little bit of work right here came in.
02:39
And instead of the letter y, we're going to put 45 minus x in here...