Substitution isn't the easiest way. Elimination is easier,
But you specified substitution, so here goes:
(1)
(2)
(3)
Pick any equation and solve for any letter:
I'll arbitrarily pick equation 2 and arbitrarily solve for y
(4)
Substitute for y in (1)
(1)
Multiply through by 4 to clear the fraction:
(5)
We notice that (3) contains the same letters as (5)
Solve (3) for one of its letters.
I'll arbitrarily solve (3) for z
(3)
(6)
Substitute in (5)
(5)
Multiply by 2 to clear the fraction:
Substitute in (6)
(6)
(4)
(x,y,z) = (2,-3,4)
Edwin
