Inequalities(2)

其實都好明顯

Q1, 當乘負數去 inequalities時,大細符號要調轉的 . 而Q1 gei只係兩邊乘負1
如果難明gei我舉個例子
-2≦1 , 但當兩邊乘負1時就會出 ,
2≧-1

Q2 , 其實同乘負數去 inequalities差唔多 , 1 over 兩邊都係要將大細符號要調轉的 .
同樣舉個簡單例子
1 / 10 > 1 /20 , 但當兩邊俾1除(即是1 over 兩邊時)就會出 ,
10 < 20

There are mistakes in highlight parts. Make necessary corrections.

Q1.

x-3≦2x+4

x-2x≦4+3

-x≦7

x≦-7<----(correct to x => -7)

Q2.

2/x＞5

(2 - 5x)/x > 0

for x > 0,

2 - 5x > 0

5x < 2

x < 2/5

hence,0 < x < 2/5

for x < 0,

2 - 5x < 0

5x > 2

x > 2/5

no solution

hence,

0 < x < 2/5