GWD1-36

[cmuboys]

Can someone tell me why the answer is E not B?
There is a graph in the question
I cannot paste the question into here
sorry

[waleaaa]

On the number line(下圖), the shaded interval is the graph of which of the following inequalities?

A.|X| ≤ 4
B.|X| ≤ 8
C.|X-2| ≤ 4
D.|X-2| ≤ 6
E.|X+2| ≤ 6

這題應該可以直接找線上的任一點代入就可以知道答案...

如果一定要公式...那我的想法是─
此線段的長度為12　中心點為-2
-2到兩端點(-8 & 4)的距離為6
所以　假設兩端點為X
公式可寫為─
X - (-2) = 6 --> X + 2 = 6
所以此線段上之任一點到中心點(-2)的距離公式即為|X+2| ≤ 6　故選E