please help me solve these

(1 point) The expression can be written as e, where f(x) is a function of x. Find f(x). f (x) =\fDetermine if each of the following functions from {a, b, c, d } to itself is one-to-one and/or onto. Check ALL correct answers. (a) f(a) = b, f(b) = a, f(c) = c, f(d) = d A. onto. B. one-to-one. C. neither one-to-one nor onto. f(a) = b, f(b) = a, f(c) = b, f(d) = c A. neither one-to-one nor onto. B. one-to-one. OC. onto. f(a) = d, f(b) = b, f(c) = c, f(d) = d A. one-to-one. B. onto. OC. neither one-to-one nor onto