To solve this question, we need to substitute the value of x = 7 into the function f(x)=10-2x, as this lies in the domain of function f(x).
Step 1: Write down the equation f(x) = 10 - 2x.
Step 2: Given x = 7, substitute x with 7 in the function. This gives f(7) = 10 - 2*7.
Step 3: Solve the equation. 10 - 2*7 equates to 10 - 14, which equals -4.
So, f(7) = -4.
Looking at the answer options provided, we find that option a is -4, which matches our calculated result.
Therefore, the correct answer to the question "Given f (x) = 10-2x, find f(7)" is option a. -4.