Question 1190554
you are simply replacing the x in f(x) with the value of x.


a.
f(x) = 3x - 4 * sqrt(x).
f(4) = 3 * 4 - 4 * sqrt(4) = 12 - 2 = 10


b.
f(x) = (x-4) * (x+3).
f(3) = (3-4) * (3+3) = -1 * 9 = -9


let me know if you have any questions.
theo