a/b=3/5 does not require a=3 and b=5
(a,b)=[(3,5), (6,10), 9,15), ... etc )
Use a=(3/5)b
then 3a+2b/3a-2b=
(9/5)b + 2b/(9/5)b) - 2b=
-b/5 + 10/9
Did you mean (3a+2b)/(3a-2b) ? Then we have
((3/5)b + 2b)/( (3/5)b - 2b) =
[(13/5)b]/[-(7/5)b]=
-13/7
2006-12-09 19:42:44
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answer #1
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answered by albert 5
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All we can do is work backwards from the original solution.
Note that both a and b must be nonzero, otherwise a/b would not equal 3/5.
First, let's see what (3a+2b)/(3a-2b) will give us.
Our first step would be to multiply the top and bottom by 1/b. This is completely a valid step because b is nonzero.
[(3a+2b)/b] / [(3a - 2b)/b]
Now, we can put them individually over b.
{ [3a/b] + [2b/b] } / { [3a/b] - [2b/b] }
[2b/b] will become 2, since the b will cancel out.
{ [3a/b] + 2 } / { [3a/b] - 2 }
Now, we will express [3a/b] as 3[a/b]
{ 3[a/b] + 2 } / { 3[a/b] - 2 }
Since it was given that a/b = 3/5, we just replace each instance of a/b with that, giving us
{ 3[3/5] + 2 } / {3 [3/5] - 2 }
And then we solve as normal.
{ [9/5] + 2 } / { [9/5] - 2 }
To get rid of the complex fraction (fractions within fractions), we multiply the top and bottom by 5, eliminating all denominators.
{ 9 + 2(5) } / { 9 - 2(5) }
{ 9 + 10 } / {9 - 10}
19/(-1)
-19
Therefore, -19 should be your final answer.
2006-12-09 19:07:06
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answer #2
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answered by Puggy 7
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a/b = 3/5. So, assuming an integer k as the common factor, a=3k, b=5k. Then, computing (3a+2b)/(3a-2b) would give you
19k/-k = -19. Thus, the answer is -19
2006-12-11 22:09:49
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answer #3
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answered by pravkas 2
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3a+2b/3a-2b
divide numerator and denominator by b so the expression becomes
[3(a/b)+2]/[3(a/b)-2]
substitute a/b=3/5
3*(3/5)+2/3(3/5)-2
=9+10/9-10
= -19
2006-12-09 18:55:57
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answer #4
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answered by xxxxxxxx 1
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a/b = 3/5
(3a+2b)/(3a-2b)
= (3(a/b)+2)/(3(a/b)-2)
= 3(3/5) +2)/(3(3/5) -2)
= (3*3+2*5)/(3*3-2*5)
=(9+10)/(9-10)
= 19/(-1)
= -19
2006-12-09 18:53:38
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answer #5
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answered by Mein Hoon Na 7
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given:a/b=3/5
3a+2b/3a-2b
dividing numerator and denominator by a we get-
numerator=3+2b/a
subtitute value of b/a in this we get-
3+2*5/3=19/3
denominator=3-2b/a
3-2*5/3= -1/3
answer is=-19
2006-12-09 21:17:34
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answer #6
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answered by rachita 1
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If a/b=3/5,then a=3 and b=5
3(3) + 2(5) / 3(3) - 2(5) = 19 / -1 = -19
-19 not equal 3/5
therefore false
2006-12-09 18:53:32
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answer #7
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answered by Rainman 5
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a/b = 3/5 then
3a + 2b/3a - 2b =
(9b/5 + 2b)/(9b/5 - 2b) =
(9 + 10)/(9 - 10) =
-19
2006-12-09 18:56:30
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answer #8
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answered by Helmut 7
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a/b=3/5 solve for a
a = 3b/5 now substitute into equation (3a+2b)/(3a-2b)
(3(3b/5) +2b)/(3(3b/5 )-2b) =
(19b/5)/(-b/5) = -19
2006-12-09 19:08:59
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answer #9
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answered by Anonymous
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a=3b/5
substitute this in the given equation
3(3b/5)+2b/3(3b/5)-2b
which gives -19
2006-12-09 19:01:19
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answer #10
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answered by ranjith 1
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