maths!!!急!!

2009-01-05 3:08 am

the length of the rectangle is 7X cm and the width is (3X + 8) CM. If the lenght is 4 CM longer than the width, find the length of the rectangle.

回答 (3)

2009-01-05 3:20 am

✔ 最佳答案

length=7X cm
width=(3X + 8) cm

7X-(3X+8)=4
4X-8=4
4X=12
X=3

length
=7X
=7*3
=21cm

參考: me

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2009-01-05 7:01 am

7X - (3X+8) = 4
7X - 3X - 8 = 4
7X - 3X = 4 + 8
4X = 12
X = 12/4
X = 3

2009-01-04 23:01:58 補充：
漏左....
the length = 7X = 7(3) = 21

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2009-01-05 3:22 am

7x = (3x+8) +4
7x= 3x+12
4x=12
x=3

2009-01-04 19:23:05 補充：
sub x =3 into 7x
7(3)
=21

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