00:01
So we have the system of equations, and we want to see if we can solve out the value of each variable using substitution.
00:09
So they give us off the bat that x is equal to 5, so we can use this to plug into one of the equations.
00:15
So we're going to have x minus y plus z is equal to 5, and i'm going to use the second equation.
00:24
So i'm going to plug in x is equal to 5 right here and get 5 minus y plus z.
00:31
Is equal to 5 so this cancels out if you subtract it from both sides and you get negative y plus z is equal to 0 so y is equal to z so that's going to be one of our substitutions that we're going to use in the third equation to solve so we're going to have x plus y minus z for the third equation is equal to negative 5 we have y is equal to z so we're going to plug that in.
01:05
So we have x, or actually we can just plug in, x is equal to 5.
01:10
So we have 5 plus z minus z is equal to negative 5.
01:19
So this comes out to 0, and we can see that 5 is not equal to negative 5...