00:01
So we have a paragraph here about purchasing avocados.
00:04
Now let's try to write this out in algebraic form.
00:07
So we want to purchase 1 ,200 worth of avocados.
00:12
So we're going to have this as x, y.
00:16
X is the price per avocado that is being sold at.
00:20
Y is the number of avocados that we try to buy.
00:26
Now, we say the avocados are too small, give us two extra for free.
00:30
Okay, so instead, we got, for our 1 ,200, we got an extra two.
00:40
Now here, i'm going to put this as x1 and x2, we're getting 100, so the seller is getting 100 per dozen less.
00:53
So this x2 is, if it's 100 per dozen, that's, well, 100 over 12 per avocado.
01:04
So 100 over 12.
01:07
Less than the previous price.
01:10
So the original price is x1.
01:12
The price that we're getting with our extra 2 is x1 minus 100 per 12 or 100 over 12 per avocado.
01:22
We want to find out y plus 2.
01:26
This is how many avocados we are getting.
01:31
Okay, so what can we do here? well let's try to organize this a little bit.
01:35
So x2 is x1 minus 100 over 12.
01:39
So i've got two equations.
01:42
1 ,200 is x1 .y.
01:45
1 ,200 is equal to x1 minus 100 over 12, multiplied by y plus 2.
01:53
So this i can expand on, which i will do now.
02:02
So we're going to have four terms.
02:04
We have x1y.
02:06
We have x1 times 2.
02:09
We have y times 100 over 12, minus 100 over 12, and we have minus 100 over 12 times 2.
02:22
There we go.
02:23
So i've just expanded those brackets there algebra equally.
02:29
Now i'm going to call this equation 1, this equation 2.
02:33
I'm going to do equation 2 minus 1.
02:37
Left -hand sides cancel out, 1 ,200, minus 1 ,200.
02:41
On the right -hand side, these cancel out, and we're just just left with 2x1 minus 100 over 12 y, and i'll throw this onto the other side, 200 over 12.
03:01
Okay, multiply everything by 12, we get 24.
03:13
Okay, let me make some space, keep working on this...