[求助]请教几道数学题

请教几道数学题

求助大牛们

1.

For which of the following functions f is f (x) = f (1 - x) for all x ?

(A) f (x) = 1 - x

(B) f (x) = 1 - x^2

(C) f (x) = x^2 - (1 - x)^2

(D) f (x) = (x^2)(1 - x)^2

Ans

2.

In a certain state, gasoline stations compute the price per gallon p, in dollars, charged at the pump by adding a 4 percent sales tax to the dealer's price per gallon d, in dollars, and then adding a gasoline tax of $0.18 per gallon.  Which of the following gives the dealer's price per gallon d in terms of the price per gallon p charged at the pump?

(A) d = p - 0.22

Ans: 想了解式子怎么列
        (形式如A选项)

3.

Before being simplified, the instructions for computing income tax in Country R were to add 2 percent of one's annual income to the average (arithmetic mean) of 100 units of Country R's currency and 1 percent of one's annual income.  Which of the following represents the simplified formula for computing the income tax, in Country R's currency, for a person in that country whose annual income is I ?

Ans: 想了解式子怎么列