1.the perimeter of a rectangle is 4x cm,if the width is 2 cm shorter than the length,find the length of the rectangle.
2.given 2consectives numbers.the smallest of which is n+1.which down the product of these 2numbers.
Maths..F.1..
2009-07-25 6:00 am
回答 (2)
2009-07-25 6:51 am
✔ 最佳答案
(1) Let the length be L cmTherefore the width is L - 2 cm
Perimeter = (L + L - 2) * 2 = 4x
(2L - 2)*2 = 4x
2L - 2 = 2x
2L = 2x + 2
L = x + 1
(2) Since the smaller number is n+1, so the bigger number is n+2
The product of these two numbers is (n+1)(n+2) = n2 + 3n + 2
2009-07-25 4:35 pm
1)Let the length of the rectangle be a cm.
2a+2(a+2)=4x
2a+2a+4=4x
4a=4x-4
a=x-1
The length of the rectangle is (x-1) cm.
2)The smallest number is (n+1)
Then the largest number is (n+2)
(n+1)(n+2)=n^2+3n+2
2009-07-25 08:36:27 補充：
Correction
1)Let the length of the rectangle be a cm.
2a+2(a-2)=4x
2a+2a-4=4x
4a=4x+4
a=x+1
The length of the rectangle is (x+1) cm.
2a+2(a+2)=4x
2a+2a+4=4x
4a=4x-4
a=x-1
The length of the rectangle is (x-1) cm.
2)The smallest number is (n+1)
Then the largest number is (n+2)
(n+1)(n+2)=n^2+3n+2
2009-07-25 08:36:27 補充：
Correction
1)Let the length of the rectangle be a cm.
2a+2(a-2)=4x
2a+2a-4=4x
4a=4x+4
a=x+1
The length of the rectangle is (x+1) cm.
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