Expert: Richard J. Raridon - 10/21/2008

Question
Solve using Cramer's rule

2a + 3b = 6
2a + b = -2

and

a + b + 5c =2
3a + b + 2c = 3
4a + 2b - c = -3

if you could let me know how you figured it out that would be great!

Answer
Cramer's rule means using determinants
The denominator determinant is
|2 3|
|2 1| which has a value of -4
for a, the numerator determinant is
|6  3|
|-2 1| which has a value of 12 so a = 12/-4 = -3
for b, the determinant is
|2  6|
|2 -2| which has a value of -16 so b = -16/-4 = 4

Do the same thing for the next set and you get
a= 2, b= -5 and c= 1