Question

X + y + z = 7 2x − y + z = 7 3x − z = 2

Answer 1

A) X + y + z = 7
B) 2x − y + z = 7

C) 3x − z = 2
C) z = 3x -2 Substituting this into equations A) and B)


A) X + y + 3x -2 = 7
B) 2x − y + 3x -2 = 7 Adding A and B
3x + 6x -4 = 14
9x = 18
x = 2
Since x = 2 then
A) 2 + y + 6 -2 = 7
A) y  = 1

A) X + y + z = 7
A) 2 + 1 + z = 7
z = 4