Monday, June 23, 2008

Wednesday, June 4, 2008

Simultaneous Equations

Algebra Problems
Let's discuss a particular technique used to solve simultaneous equations. Problem 1.
Eq.1   3x+2y=10
Eq.2 -6x+10y=4

Now, multiply the the first equation by 2.
Eq.1  2(3x+2y)=10(2) →  6x+4y=20
Eq.2     -6x+10y=4        →  6x+10y=4

When we add both equations, we are going to get
Eq.3    14y=24

Divide both sides by 14 and we get the following.
          y=24/14   →   y=12/7

We need to solve for x. We will then plug what we got for y into the first equation.
         3x+2y=10 → 3x+2(12/7)=10 → 3x+24/7=10

Subtract 24/7 from both sides.
         3x=46/7
Divide both sides by 3.


Therefore, we will get

        x=46/21

Next time the topic of partial differential equations will be our focus.