00:02
All right, so for number seven, we're checking to see if the points given in part a and part b are solutions to the system of linear equations, the same way that we've done in the first six problems.
00:15
But this time we have some fractions, which makes things a little bit more complicated.
00:21
But the rules are the same.
00:23
If we plug in x and y and the equation is true, then therefore it becomes a solution to that system of equations.
00:30
As long as it's true for both of those equations.
00:34
So starting with part a, my x value is negative 2 and my y value is 0.
00:38
I'm going to plug those into the first equation and see if it's true.
00:43
So negative 2 is equal to x, which is negative 2, minus 7 times my y of 0.
00:50
Now this is, so on the right side we have to first do negative 7 times 0, which is 0.
00:57
So all i'm left with is a negative 2.
00:59
So negative 2 is equal to negative 2.
01:01
That's a true statement, which means i need to check that point for my second line and make sure it works for that one, and then it would be a solution.
01:12
So my second line is 6x minus y equals 13.
01:15
I'm going to plug in my x and my y, so i'm going to do 6 times negative 2 minus 0 and see if that's equal to 13.
01:25
6 times negative 2 is negative 12, so negative 12 is not equal to 13.
01:32
So since that is incorrect, that means that negative 2 -0 is not a solution.
01:47
All right, so let's check another one for part b.
01:56
In this case, i'm using the fraction 1 -half as my x value and the fraction 514th as my y value.
02:06
And i'm plugging into each equation again.
02:09
So my first equation is negative 2 equals x minus, 7y.
02:16
So that means that x is one half minus seven times my y, which is 5 over 14.
02:26
Now i'm going to convert this 7 to 7 over 1 so i can multiply those two fractions.
02:31
So this becomes one half and then let's look at 7 over 1 times 5 over 14.
02:41
So i can simplify those two fractions since we're multiplying them together, the 7 can just become a 1, and the 14 a 2, because 7 over 14 would be 1 half.
02:56
So then it makes my multiplication a lot easier.
02:59
So i have, basically i have negative 1 times 5, so that's going to be my minus.
03:04
1 times 5 is 5 over 1 times 2, which is 2.
03:11
So that's good because now my denominators match and i can go ahead and simplify.
03:18
The right hand side i have one half minus five halves.
03:21
So one minus five is four...