Narayan Scribe Post for Thursday, March 27, 2008

Today, we reviewed LS-46 from yesterday. Then, we moved on to a new unit and were introduced to matrices. We completed LS-54 and 55, where we learned what matrices are and how they can be used. Other than that, we didn't do anything else today.

Substitution Method

FX-50

y=-x-2 and 5x-3y=22

5x-3(-x-2)=22
5x+3x+6=22
8x+6=22
8x=16
x=2

y=-(2)-2
y=-2-2
y=-4

x=2 and y=-4

You have a system of equations, y=-x-2 and 5x+3y=22. One of them looks easier to solve than the other, so first substitute the easier equation into the harder one and simplify. Once you do that, you should have the equation 5x+3x+6=22. Now, go ahead and solve for x. You found that x=2, so substitute 2 for x in the first equation and you can solve for y. You should get y=-4. So x=2 and y=-4. Now you have solved the system of equations.