GRE
$$a^{c-d}$$
$$b^{d-c}$$
3x
$$\sqrt{45}$$
$$3^{x}$$
$$3^{-x}$$
n
k +1
$$x$$ +$$x^{-1}$$
2
$$\sqrt{xy}$$
$$\frac{x+y}{2}$$
The ratio of the number of female students to the number of male students in French class
The ratio of the number of female students to the number of male students in the school
25000 +道题目
200本备考书籍