00:02
So for this problem, we're going to use theorem 2 from section 6 .3 to say that 5y is going to be equal to 9 z plus 2.
00:26
And similarly, we can still use this theorem 2 to say that 2y plus 7 is equal to 7.
00:42
So that theorem says that the opposite sides of the quadrilateral, if opposite sides are parallel, or if opposite sides are congruent, then it's a parallelogram.
00:57
So we just need to solve y and z here.
01:04
But to do this, we're going to need to use system of equations.
01:09
So what we want to do is i'm going to bring this 9z to this other side.
01:17
So instead i'm going to have 5y minus 9z is equal to 2.
01:27
And then 2y.
01:29
So here i'm going to bring the 7 z over and then i'm going to bring the 7 to the right hand side.
01:35
So i'm going to have 2y minus 7 z is...