Using elimination: add equation 1 and equation 3 to
eliminate z
x+4y-5z=-7
2x+y+5z=8
will
result to
3x +
5y = 1
Using
eqution 2 and 1.
3( x+4y-5z=-7) >> 3x
+12y – 15z = -21
5(3x+2y+3z=7) >> 15x
Add the
two equation, to eliminate z
18x +
22y = 14
Solving
x and y from the generated equation
X = 2
Y =
-1
T
hen
substitute x and y yo any equation and solve for z
Z = 1
