إذا كانت د(س) = س - ٥ ، فإن د(١) = ...

Here's the solution for the first question:

Question 1: إذا كانت د(س) = س - ٥ ، فإن د(١) = ... Translation: If $f(x) = x - 5$, then $f(1) = ...$

Step 1: Identify the given function. The function is: $f(x) = x - 5$

Step 2: Substitute the value $x=1$ into the function. To find $f(1)$, replace $x$ with $1$: $f(1) = 1 - 5$

Step 3: Calculate the result. $f(1) = -4$

The value of $f(1)$ is: $\boxed{-4}$