00:01
So we have two equations, two unknowns here, and we're asked to use combination, linear combinations to solve for x and y.
00:07
Now, i'm looking at the first equation here, and i realize i can simplify it if i just divide everything by 4.
00:15
So let's do that first.
00:19
So 12x divided by 4, that's 3x, minus 4, y divided by 4, that's just minus 1, equals negative 8.
00:28
That makes, that simplifies things for us.
00:31
So now we have 3x minus y is negative 8, x plus 3y is 4.
00:42
So now let us start multiplying each by the coefficient of the other.
00:51
So here i have 3 and 1 for x.
00:56
Let's multiply the first by negative 1 and multiply the second by 3.
01:03
So that'll give minus 3x plus y, 8.
01:10
The next one is 3x plus 9y is 12.
01:16
Now we add both terms...