How do you get x= y=, z= (Never been taught)?

Question

-1x - 2y + 5z = 34
-5x + 2y + 3z = 38
-4x + 2y - 4z = -8

Answer 1

just an example...
set the first equation equal to x.
... x= 5z-34-2y
take that equation and plug it into the x variable for the second equation.

-5(5z-34-2y)+2y+3z=38
take this equation and solve for y

-25z+170+10y+2y+3z=38
y=(11z-66)/2

Take the x and y values and plug them into any equation and solve for z and then you're set! I'll plug mine back into the first equation.

-1[5z-34-2((11z-66)/2)]-2((11z-66)/2)+5z=34

Answer 2

if you have studied higher maths then:
you could use cramer's rule or the matrix method
http://en.wikipedia.org/wiki/Cramer%27s_rule
or solve the first two the way you normally do, then solve the next two and then solve the solutions which will be in terms of x and y.

Answer 3

first eliminate any term either x,y,z
suppose if u eliminate z in first two equation ,multiply x,y,zand consant term by 3and then 2nd equation mulitply x,y,zand consant term by 5 and u get x,y and there is no z term as it eliminated and u get x and y and substitute in 3rd equation u get z term.