GRE
$$x^{2}-7x$$
-7x+49
$$\frac{6a^{2}+12ab+6b^{2}}{a+b}$$
6((a+b)
$$(141)^{2}-(28)^{2}$$
$$(141-28)^{2}$$
$$\sqrt{x^{12}}-y$$
$$(x^{3}+\sqrt{y})(x^{3}-\sqrt{y})$$
$$(s+t)^{2}$$
$$s^{2}+t^{2}$$
y
3
The ratio of a to b
$$\frac{1}{2}$$
$$\frac{5}{6}$$
$$\frac{a}{b}$$
25000 +道题目
6本备考书籍
