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Question 1142298: One of my math problems asks that you use Cramer's rule to solve this linear system.
5x+10y=70
5x+25z=270
10y+25z=300
When I put zeros on the third column to make it a 3x3 because it has to be the same I get 0. Please help me solve this problem
Found 3 solutions by Alan3354, Edwin McCravy, ikleyn:
Answer by Alan3354(69443)   (Show Source):
Answer by Edwin McCravy(20059)  (Show Source):
You can put this solution on YOUR website! use Cramer's rule to solve this linear system.
Write it this way with 0 coefficients for the missing letters:
We begin by finding the determinant  . It consists
of just the three columns of x, y, and z coefficients,
in that order, but does not contain the constants, the
three numbers to the right of the equal signs.
 .
It has value  .
Next we find  .
Dx has all the same elements as D except that the 1st column is replaced by
the three numbers that occur after the equal signs in the system, in the
order that they occur top to bottom:
 .
It has value  .
Next we find  .
Dy has all the same elements as D except that the 2nd column is replaced by
the three numbers that occur after the equal signs in the system, in the
order that they occur top to bottom:
 .
It has value  .
Next we find  .
Dz has all the same elements as D except that the 3rd column is replaced by
the three numbers that occur after the equal signs in the system, in the
order that they occur top to bottom:
 ..
It has value  .
The values for x, y, and z are:
If you don't know how to find the value of a 3×3 determinant,
go here:
https://www.youtube.com/watch?v=V3e7m-qFDFU
Edwin
Answer by ikleyn(52798)  (Show Source):
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