GRE
(3p+1)(3p-1)
$$9p^{2}$$
(a + 2)(3a + 6)
(3a + 2)(a + 6)
$$3^{2}-2^{2}$$
$$(3-2)(3+2)$$
(–a – 10)(10 + a)
10
y
3
The number of pillows that Ann must sell for her net profit to be zero
20
$$x^{4}$$
$$y^{4}+1$$
25000 +道题目
6本备考书籍