00:01
Okay, we're going to solve this system with substitution.
00:04
And so the first thing i do with systems with decimals is multiply by 10, because i want to get rid of that decimal.
00:12
And if we multiply by 10, our decimal just moves over for each one.
00:16
So that's going to turn everything into a full number.
00:21
So i'm going to say 3x minus 1y equals 21, and we just have to be careful and make sure we do it for every single term.
00:30
And then for the bottom one, i'm going to say 6x plus 3y equals negative 3.
00:37
We're not going to mess with that negative.
00:40
So now let's get a variable by itself.
00:45
I'm going to focus on this first equation.
00:48
So i'm going to swap our y and our 21.
00:51
I'm going to add 1y, and i'm going to subtract 21.
00:55
So that will give us 3x minus 21 equals positive y.
01:02
And so now we can substitute that into the second equation...