20

15

12

9

$\frac{x}{4}$

$\frac{x}{2}$

$x$

$\frac{3x}{4}$

$\frac{2}{3}\le x\le 4$

$x\le \frac{-5}{3}$

$\frac{-5}{3}\le x\le \frac{7}{3}$

$x\ge -\frac{7}{3}$

$\mathrm{\pi }$

1

2

$0$

1

$e^{10}$

$e^5$

$\alpha$

A

$A\cup B$

$A\cup B\text{'}$

$A\text{'}\cup B$

160$°$

30$°$

150$°$

120$°$

-1

11

19

9

1

$0$

$(2-\sqrt{2})$

$(2-\sqrt{3})$

$\frac{P.x}{P-Q}$

$\frac{Q.x}{P+Q}$

$\frac{P.x}{P+Q}$

$\frac{x}{P+Q}$

-1

$0$

1

2

-3

5

7

8

$\frac{1}{\sqrt{4}}$

$\frac{1}{\sqrt{2}}$

$\frac{1}{\sqrt{3}}$

$\frac{1}{\sqrt{5}}$

x+y=2

x-y=0

x-y+5

x+y+2=0

$\frac{f}{2g+f}$

$\frac{f}{2g-f}$

$\frac{f}{g+2f}$

$\frac{f}{g-2f}$

6

3

5

4

$\frac{x}{x+1}$

$\frac{x+1}{x}$

$\frac{x}{x-1}$

$\frac{x-1}{x}$

$\frac{10}{99}$

$\frac{1}{10}$

$\frac{1}{11}$

$\frac{4}{33}$

$(0.01{)}_2$

$(10.01{)}_2$

$(0.001{)}_2$

$(0.11{)}_2$

4

-3

$\frac{1}{2}$

1

$-\frac{1}{2}$

$\frac{1}{2}$

$-1$

1

$9x^2-y^2=14$

$x^2-y^2=12$

$16x^2-9y^2=144$

$x^2-9y^2=14$

$1:\sqrt{3}$

$1:\sqrt{2}$

$\sqrt{2}:\sqrt{3}$

$\sqrt{3}:\sqrt{2}$

10

1

-1

-10

$2\overrightarrow{b}-\overrightarrow{a}$

$\overrightarrow{b}-2\overrightarrow{a}$

$2\overrightarrow{a}-\overrightarrow{b}$

$\overrightarrow{a}-2\overrightarrow{b}$