Posted on

Solve the system of equations (conics)

Q:  Solve the system of equations (both of which are conic sections)
1:   x2 + y2 – 20x + 8y + 7 = 0
2:  9x2 + y2 + 4x + 8y + 7 = 0

A:  I am going to solve this by using the elimination method (since I see that I can cancel out all of the y’s)

I am going to multiply equation 1 by (-1) and then add it to equation 2:

2:  9x2 + y2 + 4x + 8y + 7 = 0

1: -x2 – y2 + 20x – 8y – 7 = 0   [after it has been multiplied by -1]

Now, add them together to get equation 3:

3:  8x2 +24x = 0

Continue reading Solve the system of equations (conics)

Posted on

Solve the system by using matrices (and inverse matrices)

Q:  Solve the system of equations by using matrices (and inverse matrices)

7x + 5y = 3

3x – 2y = 22

Answer:

Okay, first set up the coefficient matrix (A), the variable matrix (X) and the “answer matrix” (B) so that:

Continue reading Solve the system by using matrices (and inverse matrices)