Answer:
f(10) means to input x = 10 into the function.
From inspection of the given function:

the "10" is the numerator of the fraction.
Therefore, swap the "10" for "x" to give the function in terms of x:

Answer:
1196 mm^2
Step-by-step explanation:
That's really well described. All in all you have 6 squares all laid out flat. Each square has a side of 14 mm.
The area of 1 square = 14mm * 14mm = 196 mm^2
The area of 6 squares = 6 * 196 mm^2 = 1176 mm^2