What is the value of x + y + z when 6x + 5y - 2z = - 4 and 4x + 5y + 12z = 54?

5

Step-by-step explanation:

First you would need to add the two equations.

6x + 5y - 2z = - 4 + 4x + 5y + 12z = 54

Doing this, you would get:

10x+10y+10z=50

Then, divide all parts of the equation by 10 to isolate the variables.

So,

10x+10y+10z=50/10 =

x+y+z = 5