GRE
$$x$$
$$5$$
$$t$$
$$3$$
The price of commodity X at the beginning of last year
The price of commodity X at the end of last year
$$\frac{nx+py}{n+p}$$
$$\frac{x+y}{2}$$
$$x^{2}+1$$
$$x+\frac{7}{8}$$
25000 +道题目
236本备考书籍