1 . A( 4 , -1 ) , B (-2 , -1 ) , C ( -2 , 3 ) and D ( 4 , 3) are four pionts in a rectangular coordinate plane . Given that ABCD is a rectangle , what is its perimeter ? ( Ans : 20 units )
2. If the distance between the two given points M ( 2a + 1 , 0 ) and N ( 4a + 3 , 0 ) is 6 units , find the two possible values of a . ( Ans : 2 , -4 )
2條F1.數-(急)Coordinates(要式)!!
2009-02-20 2:16 am
回答 (2)
2009-02-20 3:00 am
✔ 最佳答案
1,(length of AB + length of AD) x 2= [ 4-(-2) + 3-(-1) ] x 2
= 20
2. length of MN = 6
|2a+1 - (4a+3)| = 6
2a+1-4a-3=6 or 2a+1-4a-3 = -6
-2a-2=6 or -2a-2=-6
-2a=8 or -2a=-4
a=-4 or a=2
2009-02-20 2:42 am
1,(length of AB + length of AD) x 2
= [ 4-(-2) + 3-(-1) ] x 2
= 20
2. length of MN = 6
|2a+1 - (4a+3)| = 6
2a+1-4a-3=6 or 2a+1-4a-3 = -6
-2a-2=6 or -2a-2=-6
-2a=8 or -2a=-4
a=-4 or a=2
= [ 4-(-2) + 3-(-1) ] x 2
= 20
2. length of MN = 6
|2a+1 - (4a+3)| = 6
2a+1-4a-3=6 or 2a+1-4a-3 = -6
-2a-2=6 or -2a-2=-6
-2a=8 or -2a=-4
a=-4 or a=2
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