00:01
One month, my rented five movies and three video games for $39.
00:14
The next month, she rented two movies and 12 video games for $75.
00:27
You're wondering the total cost of movies and the total cost of video games.
00:37
We need to create equations for both of these.
00:44
We'll call movies m.
00:47
5m plus 3 games equaled $39.
00:53
And here, two movies and 12 games equaled 75.
01:00
What we need to do is isolate one of these variables and use the substitution method.
01:05
In the second equation, let's isolate m.
01:09
I'm going to subtract 12g from both sides to get 2m equals 75 minus 2.
01:19
And then divide everything by two to see what m equals.
01:24
I get m equals 75 over 2, which is 37 .5 minus 6g.
01:34
What i'm going to do is take this equation and replace it with m in the first equation.
01:40
That's called the substitution method of solving in algebra.
01:45
I have 5 times m.
01:51
But instead of m, i'm going to replace it with what i now have to substitute in for m, 37 .5 minus 6g, plus 3g equals 39.
02:04
We need to distribute that 5.
02:07
5 times 37 .5 gets me 187 .5...