Substituting Functions: Simplifying Multivariate Expressions

[fred2028]

This is more of a concept question, so the template is not followed.

Say you're given

T(x,y,z) = xy-z

And

z = x+y

Basically, T is a function of x, y, and z while z is a function of x and y. If we substitute z into T, would T become T(x, y) or stay T(x, y, z)?

 

[rock.freak667]

Your function would become T(x,y)

 

[fred2028]

Your function would become T(x,y)

OK thanks!