Solving for y

learningmathagain

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Jun 28, 2020
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When x=2 and y=3, (xy+3)1/4((x+y)1/2−(y−1)x−1) = ?

The answers are given as multiple choice and I can't seem to get the right one. Here's my expanded equation:

(2*3+3)1/4((2+3)1/2 - (2-1)(3-1) = ?

91/4 (51/2 - 2/2) = ?

91/4 (51/2 - 1) = ?

91/4 (51/2) - 91/4 = ?

And here's where I get stuck. I'm not sure how to simplify this more, but apparently the answer is 151/2 - 31/2 but I'm not sure how that is. Would be happy for some help!
 

R.M.

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Aug 5, 2019
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56
91/4 = (91/2)1/2 = (32x1/2)1/2 = 31/2
See what you can do with this.
 

pka

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Jan 29, 2005
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10,453
You should give all the choices so that we can see what is going on.
I see one mistake in the first line:
if \(x=2~\&~y=3\) then \((y-1)x^{-1}=(2)(2)^{-1}=1\)
 

Jomo

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Dec 30, 2014
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(2-1)(3-1)
Although that 3 should be a 2 I am still interested in how you got 2/2. Please show those steps.
 

Jomo

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Dec 30, 2014
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91/4 = (91/2)1/2 = ....
 

Subhotosh Khan

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When x=2 and y=3, (xy+3)1/4((x+y)1/2−(y−1)x−1) = ?

The answers are given as multiple choice and I can't seem to get the right one. Here's my expanded equation:

(2*3+3)1/4((2+3)1/2 - (2-1)(3-1) = ?

91/4 (51/2 - 2/2) = ?

91/4 (51/2 - 1) = ?

91/4 (51/2) - 91/4 = ?

And here's where I get stuck. I'm not sure how to simplify this more, but apparently the answer is 151/2 - 31/2 but I'm not sure how that is. Would be happy for some help!
(2*3+3)1/4((2+3)1/2 - (3-1)(2-1) = ?

91/4 (51/2 - 2/2) = ?

91/4 (51/2 - 1) = ?

91/4 (51/2) - 91/4 = ? ..................... You are almost there...

31/2 (51/2) - 31/2

= (3*5)1/2 - 31/2 .......continue.....
 

learningmathagain

New member
Joined
Jun 28, 2020
Messages
2
91/4 = (91/2)1/2 = (32x1/2)1/2 = 31/2
See what you can do with this.

Thank you! That made everything more clear, I didn't think to simplify this further.
 
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