急...幫我計下哩幾條數丫~吾該(10分)

2008-12-01 6:28 pm

幫我長細d寫丫~
1. Find the value of x
120x + 200(5500- x ) = 916000

2 .Find a
3a +(2a -1)+(4a +2) = 91

3.Find x
(3x +2) +(4x -1)+(x +20) = 69

更新1:

4.Find the value of x [( 2x - 6 )+1/2 x ]*2 = 7*4

更新2:

Bobby buys x pieces of fruit tarts and eats 1/4 of them. is brother and sister eat 7 pieces in total and therer are pieces left. Findthe value of x?

回答 (2)

用戶8785

2008-12-01 7:09 pm

✔ 最佳答案

Q1)
120x + 200( 5500 - x ) = 916000
3x + 5( 5500 - x ) = 916000/40
3x + 27500 -5x = 22900
-2x = -4600
x = 2300

Q2)
3a + ( 2a - 1 ) + ( 4a + 2 ) = 91
3a + 2a -1 + 4a + 2 = 91
9a + 1 = 91
9a = 90
a = 10

Q3)
( 3x + 2 ) + ( 4x - 1 ) + ( x + 20 ) = 69
3x + 4x + x + 2 - 1 + 20 = 69
8x + 21 = 69
8x = 48
x = 6

Q4)
[ ( 2x - 6 ) + x/2 ] * 2 = 7 * 4
2( 2x - 6 ) + x = 28
4x - 12 + x = 28
5x -12 = 28
5x = 40
x = 8

參考: myself..

👍 0 👎 0

2008-12-02 5:52 am

1)
120x+200(5500-x)=916000
120x+1100000-200x=916000
80x=184000
x = 2300

2)
3a+(2a-1)+(4a+2)= 91
3a+2a-1+4a+2=91
9a=90
a=10

3)
(3x+2)+(4x-1)+(x+20)=69
3x+2+4x-1+x+20=69
8x=48
x=6

4
[(2x-6)+x/2]*2=7*4
2(2x-6)+x=28
4x-12+x=28
5x=40
x=8

5
做唔到......因為個題目冇比到剩下多少個

參考: 自己個腦=w=

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