1/3x +1/4 = 5/2x +7 Solve for x?

2008-12-04 7:51 am

I keep coming up with x = 81/26, and I don't know what I'm doing wrong. Can anyone shed some light on this for me?

更新1:

1 1 5 --- x + --- = --- x + 7 3 4 2 OK... I hope that this looks better! Let me know what you guys come up with! I really appreciate your help!

更新2:

1 1 5 -x +- = -x + 7 3 4 2

更新3:

Ok, I finally figured out how to write this correctly! Thanks for bearing with me! (1/3) x + 1/4 = (5/2) x + 7

回答 (4)

[匿名]

2008-12-04 7:56 am

✔ 最佳答案

If 1 / 3x + 1/4 = 5 / 2x + 7:

The denominators: 3x, 4, and 2x
The LCD: 12x

Multiply each term by the LCD:
(12x)(1/3x) + (12x)(1/4) = (12x)(5/2x) + (12x)(7)
Simplify:
4 + 3x = 30 + 84x
84x - 3x = 4 - 30
81x = -26
x = -26/81 Answer

If (1/3)x + 1/4 = (5/2)x + 7

Denominators: 3, 4, and 2
LCD: 12

Multiply each term by the LCD:
12(1/3)x + 12(1/4) = 12(5/2)x + 12(7)

4x + 3 = 30x + 84
4x - 30x = 84 - 3
-26x = 81
x = -81/26 Answer

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An ESL Learner

2008-12-04 9:03 am

1/3(x) + 1/4 = 5/2(x) + 7
x/3 + 1/4 = 5x/2 + 7
x/3 - 5x/2 = -1/4 + 7
12(x/3 - 5x/2) = 12(-1/4 + 7)
4x - 30x = -3 + 84
-26x = 81
x = 81/-26
x = -81/26

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[匿名]

2008-12-04 7:57 am

Do you mean 1/(3x) or (1/3)x ?

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