The Domain of an Algebraic Expression: Only addition and subtraction

What will be the result of this algebraic expression:

$5x-6$

if we place

$x=0$

Usually we don't know the value of the unknown and need to find it,

However, in this case they give us a value, so the first action will be to substitute it into the expression,

Meaning, replace every place where X is written with 0.

5*0-6=
0-6=-6

Therefore, the result is -6.

$-6$

What will be the result of this algebraic expression:

$5x-6$

if we place

$x=8$

34

What will be the result of this algebraic expression:

$5x-6$

if we place

$x=-2$

$-16$