example:
Find the smallest interal value of x which satisfies the inequalities
3 - 3x ＜ x - 5 or 3x^2 - 8x - 16 ≦0
x ＞2 or -4/3≦x≦4
the solutions are x≧-4/3
the smallest intergralvalue of x which satisfy the inequalities is -1
点解solutions要係 x≧-4/3 ???????????
smallest intergralvalue of x which satisfy the inequalities 係乜意思?個-1係点樣求出黎?
有D A math唔明
2006-10-20 5:16 am
回答 (2)
2006-10-20 5:42 am
✔ 最佳答案
3-3x < x-5 or 3x^2-8x-16≦0so 8<4x or (x-4)(3x+4)≦0
so x>2 or -4/3≦x≦4
因為係or,
所以x只要符合其中一邊就成立
一邊係x大過2就得
另一邊就要x在 -4/3同4之間
x>2就即係話大過2既數都符合條式
而另一邊就係細過4
咁即係話所有數都可以成立
但係就唔可以細過-4/3
細過-4/3就唔符合第二條inequality
亦唔符合第一條 (x要大過2)
所以一定要大過-4/3
所以solution is x≧-4/3
至於smallest intergralvalue of x which satisfy the inequalities 就係解要一個最細既整數符合這2條inequalities
咁依家x要大過-4/3
-4/3唔係整數(-1.3333333)
咁最細既整數就係-1了
希望可以幫到你
參考: 自己
2006-10-20 5:28 am
3 - 3x ＜ x - 5 ,
x ＞2
3x^2 - 8x - 16 ≦0 ,
-4/3≦x≦4
because x≧-4/3 , x ＞2 , x≦4,
so smallest intergralvalue of x which satisfy the inequalities x≧-4/3,
(because the smallest "value" is -4/3)
x ＞2
3x^2 - 8x - 16 ≦0 ,
-4/3≦x≦4
because x≧-4/3 , x ＞2 , x≦4,
so smallest intergralvalue of x which satisfy the inequalities x≧-4/3,
(because the smallest "value" is -4/3)
收錄日期: 2021-04-12 22:33:27
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20061019000051KK04242