Question

i needed to edit this question :p

Answer 1

first make two equations in two variables by eliminating one variable
then solve these two equations by elimination or by substituting or by any other method namely matrces etc.

Answer 2

you can eliminate any out of x,y,z from these three equtions

Answer 3

Ohhh okay

Answer 4

here eliminate z or x will be easier.

Answer 5

multiply (1) by2 and subtract from (2)again multiply (1) by 2 and subtract from (3)
you get two equations in x and y