00:01
In this problem, we're being asked to solve the given system of equations.
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Now they even gave you a hint in your directions to get rid of our fractions.
00:09
That way it will make our life easier.
00:11
So how do we get rid of fractions in an equation? well, we have to multiply the whole equation by our common denominator.
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So if i'm looking at this first equation, we have denominators of 4, 3, and 12.
00:21
So our common denominator would be 12.
00:23
So i'm gonna multiply the whole equation by 12.
00:25
Well, 12 times negative 3 4ths, 4 goes into 12 three times, so really we're just doing 3 times negative 3x, which would be negative 9x.
00:35
Then i'll bring that 12 again.
00:36
Then we're gonna multiply 12 times y over 3.
00:39
Well, 3 goes into 12 four times, so really we have 4 times y, which is 4y.
00:45
Then if i bring that 12 back, we're gonna multiply 12 by negative 5 over 12.
00:49
Well, 12 goes into 12 one time, so really we're just left with negative 5.
00:55
Alright, so now let's take a look at the second equation.
00:58
We only have two fractions in this case, so what we have to find their common denominator.
01:02
Well, the common denominator for 12 and 5 would be 60.
01:06
So let's go ahead and distribute.
01:07
So first, 60 times negative 5 12ths.
01:10
Well, 12 goes into 60 five times, so 5 times negative 5x would be negative 25x.
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Then we'll bring the 60 back.
01:17
60 times negative y, that's just negative 60y.
01:20
And then we'll have 60 times negative 4 5ths.
01:24
Well, 5 goes into 60 12 times, so 12 times negative 4 would be negative 48.
01:30
Okay, great.
01:30
Now we got rid of the fractions.
01:32
Now we can solve by either elimination or substitution.
01:35
I'm gonna do elimination, meaning that when i add the two equations together, i want one of the variables to cancel out.
01:42
So i'm gonna focus on our y's...