Question

Given that 4x-y=5 4y-z=7 and 4z-x=18 what is the value of x+y+z

Answer 1

Answer:

x + y +z= 10

Step-by-step explanation:

4x - y = 5  ---------(I)

 4y - z = 7 ---------(II)

4z - x = 18 ---------(III)

Add all the three equations,

  4x - y + 4y - z + 4z - x = 5 + 7 + 18

  4x - x  -y + 4y -z + 4z  = 30

              3x + 3y + 3z = 30

Divide the entire equation by 3

               $\sf \dfrac{3x}{3}+\dfrac{3y}{3}+\dfrac{3z}{3} = \dfrac{30}{3}$

                 x + y + z = 10

Answer 2

Using simultaneous equations,
x=2, y=3, z=5.

Therefore x+y+z
=2+3+5
=10