hello
in this question, we have z + y - 6 = 0
y = 6 and z = 2
substitute z and y into the equation
[tex]\begin{gathered} \text{ z }+\text{ y }-\text{ 6 }=0 \\ y\text{ }=\text{ 6 } \\ z\text{ }=\text{ 2} \\ \text{substitute y and z into the equation} \\ 6\text{ }+\text{ 2 - 6 }=2 \\ \end{gathered}[/tex]the answer is equal to 2
just substitute z and y into the equation
