Put in 1 or -1 coefficients, and +0y for the missing term in
the 2nd equation. Put 0x for the missing term in the third
equation:
Form the denominator determinant by using only the coefficients
to the left of the = sign. You don't use the red numbers in D,
but you will in the others:
= 21
[Do you know how to evaluate a 3x3 determinant?
If not, post again asking how to. I will assume
you already know how. That's where I got the 21.]
x is the FIRST unknown and so is just like
except that the FIRST column is replaced by the three red numbers,
which I made up:
= -42
y is the SECOND unknown and so is just like
except that the SECOND column is replaced by the three red numbers:
= 0
z is the THIRD unknown and so is just like
except that the THIRD column is replaced by the three red numbers:
= 105
So:
Then the solutions are given by:
== = == = = =
Edwin
