sytem of linear equations solve
x+y+4z=-11
x+y+6z=-15
x+8y+8z=-26

Question

sytem of linear equations solve 
x+y+4z=-11
x+y+6z=-15
x+8y+8z=-26

hero · Answer

Hint, isolate z in the first equation, then substitute the expression for z into the last two equations.

anonymous · Answer

We shall begin by getting rid of the x.
x+y+4z=-11
-1(x+y+6z=-15)            <-- Must make it negative to cancel it out

x+y+4z=-11
-x-y-6z=15                   <-- New equation after you multiply the -1
=  -2z=4   z=-2            

Now you solve for the other equation.

x+y+4z=-11
-x-8y-8z=26
Answer=  -7y-4z=15               <-- Plug in -2 for z

-7y+8=15
y=-1

plug in -2 for z and -1 for y in any of the first 3 starting equations to solve for x.