00:03
If we want to solve the system with the elimination method, we need to change the equations into standard form.
00:09
So for the first equation, we'll add 14 to both sides, and we get 7x plus 4y equals 14.
00:16
For the second equation, we'll subtract 2y from both sides, and we get 3x minus 2y equals negative 20.
00:24
Okay, next we want to find a way to eliminate either x or y.
00:32
So we need opposite coefficients on x or opposite coefficients on y.
00:37
And right now we don't have either one of those.
00:40
However, if we were to multiply the second equation by 2, then we would have a negative 4y, and then the first equation has a positive 4y.
00:51
Those would be opposites.
00:52
So multiplying the second equation by 2 gives us 6x minus 4y equals negative 40 for that equation, and leaving the first equation the same gives us 7x plus 4y equals 14.
01:08
Now we add the equations together, add the x terms, and we get 13x, the y terms are eliminated, and add the constants, and we get negative 26.
01:20
Divide both sides of that equation by 13, and we have x equals negative 2.
01:25
Now we need to find the value of y.
01:28
So we're going to take our value negative x, of 2 is negative negative.
01:32
Of x negative 2 and substitute it into either equation 1 or equation 2...