How to solve this rational equation?

👨🏻‍🏫 學術台數學

[匿名]

2009-06-04 10:22 am

I'm having trouble solving this problem. The answer is supposed to be y = 6, but I keep getting something different.

y - 1/5 + 2 = 2y - 3/3

更新1:

Sorry guys, actually the problem is supposed to read y - 1 all over 5 + 2 = 2y - 3 all over 3. I think you have to cross multiply? I'll try to show it here: y - 1 2y - 3 ___ + 2 = _____ 5 3

更新2:

Oops, it came out kind of sloppy lol. But hopefully you can tell how everything lines up :]

回答 (6)

Engr. Ronald

2009-06-04 11:01 am

✔ 最佳答案

y-1.........2y-3
[-----+2=---------- ]15
5.............3

3(y-1)+2(15)=5(2y-3)
3y-3+30=10y-15
3y+27=10y-15
3y-10y=-15-27
-7y=-42
y=6 answer//

👍 0 👎 0

[匿名]

2009-06-04 5:32 pm

y - 1/5 + 2 = 2y - 3/3
y = - 1/5 + 10/5 + 5/5
y = 14/5 or 2 4/5

Answer: y = 14/5 or 2 4/5

Proof:
14/5 - 1/5 + 2 = 2(14/5) - 3/3
13/5 + 10/5 = 28/5 - 5/5
23/5 = 23/5

👍 2 👎 0

[匿名]

2009-06-04 5:35 pm

y - 1/5 + 2 = 2y - 3/3
y - 0.2 + 2 = 2y - 1
-0.2 + 2 = y - 1
3 - 0.2 = y
2.8 = y
Hmm..
Either the back of the book is wrong or the problem is copied down wrong.

👍 1 👎 0

An ESL Learner

2009-06-04 6:07 pm

(y - 1)/5 + 2 = (2y - 3)/3
15[(y - 1)/5 + 2] = 15[(2y - 3)/3]
[15(y - 1)/5 + 15(2) = [15(2y - 3)]/3
3(y - 1) + 30 = 5(2y - 3)
3*y - 3*1 + 30 = 5*2y - 5*3
3y - 3 + 30 = 10y - 15
3y - 10y = 3 - 30 - 15
-7y = -42
y = -42/-7
y = 6

👍 0 👎 0

[匿名]

2009-06-04 5:46 pm

If the answer is supposed to be 6, then the equation must be this one:
(y-1)/5 + 2 = (2y-3)/3
* y-1 and 2y-3 should be taken as a quantity.
You forgot to include those grouping symbols. Grouping symbol is so important in solving algebraic equation.

-->(y-1)/5 + 2 = (2y-3)/3
-->[ (y-1)/5 + 2 = (2y-3)/3 ] (15)
-->3(y-1)+30=5(2y-3)
-->3y-3+30=10y-15
-->3y-10y=-15+3-30
-->-7y=-42
-->y=-42/-7
-->y=6

👍 0 👎 0

[匿名]

2009-06-04 5:28 pm

y - 2y - 1/5 + 2 + 3/3 = 0

-y - 0.2 + 2 + 1 = 0

-y + 2.8 = 0

y = 2.8

If the answer should be 6, the question is wrong :)

👍 0 👎 0

收錄日期: 2021-05-01 12:26:38
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20090604022256AAjvalj

檢視 Wayback Machine 備份