中四數學問題

幾時先要轉中間「<」o既方向?!
答案係當乘或除一個負數果陣就要轉啦

2007-08-14 10:41:54 補充：
Find the range of values of x which satisfy both 3x - 4 2(x-1) and x 2(x-1) 3x - 4 2x - 2 x 2x

2007-08-14 10:45:57 補充：
3x - 4 大於 2(x-1)3x - 4 大於 2x - 2 x 大於 2 x 小於 6the range of values of x is between 3 to 5 (因為x 大於 2 ,, 不是 = 2 ,,又小於 6 ,,不是 = 6 ,,so x is between 3 - 5)點解你地 d 中四數咁淺..我中二都識 @@

Find the range of values of x which satisfy both 3x - 4 > 2(x-1) and x < 6
3x - 4 > 2(x-1) and x < 6
3x -4 > 2x -2 and x < 6
3x - 2x > -2 + 4
x > 2 and x< 6
so 2 < x < 6

每當兩邊同乘或除一個 負數 先要轉方向
e.g.
-32 x > 64
x < -2 （兩邊同除 -32）

1) 3x-4> 2(x-1)

3x-4> 2x-2

x> 2

range: 6>x>2

其實對於呢類問題, 首先把 [<] 或[>] 睇成 [=]. 甘就唔會有問題. 然後再好似平時 [=] 甘計, 就唔會產生混亂 (因為好多做inequality問題嘅人都俾[<] / [>] 搞亂咗! 其實最穩陣就係check數)

Shadow.

Find the range of values of x which satisfy both 3x - 4 > 2(x-1) and x < 6
3x - 4 > 2(x-1) and x < 6
3x -4 > 2x -2 and x < 6
3x - 2x > -2 + 4
x > 2 and x< 6
so 2 < x < 6

每當兩邊同乘或除一個 負數 先要轉方向
e.g.
-32 x > 64
x < -2 （兩邊同除 -32）

3x-4 > 2(x-1) and x < 6
3x-4-2x+2 > 0 and x < 6
x > 2 and x < 6

So the solution is 2<6

係丫......當要乘或者除負數就要轉.....

2007-08-14 10:46:33 補充：
小左既= =係 2 < x < 6

Find the range of values of x which satisfy both 3x - 4 > 2(x-1) and x < 6
呢題既答案係 x<2

3x - 4 > 2(x-1)

3x-4 >2x-2
3x >2x+2
x >+2

另一個問題唔識