[MOVED] Need help with A-level Math Problems -Algebra-

[GHJ]

Can you please help me with this, I don't know where I made a mistake. The anwser needs to be -2,16
And at top it says when m=2.25

 

[HallsofIvy]

I just cannot read what you have written. Perhaps others can.

 

[GHJ]

I can rewrite it

 

[GHJ]

I just cannot read what you have written. Perhaps others can.

maybe you can read it now..

 

[stapel]

maybe you can read it now..

Not really... My guess is that the exercise is meant to be as follows:

Evaluate the expression, given that m = 2.25:

. . . . .\(\displaystyle \left(A\, -\, \sqrt{m\,}\right)^2\, -\, \left(A\, +\, \sqrt{m\, }\right)^2 -\, \dfrac{4\left(m\, -\, \sqrt{mn\,}\right)^2}{\sqrt{m\,}\, -\, \sqrt{n\,}}\)

However, no values seem to have been provided for A and n...? Also, the above is just an algebra "evaluation" exercise, not a graduate-school "Advanced Math" problem, which adds to the confusion.

Kindly please reply with the full and exact text of the exercise, including the complete instructions. Also, please specify if what you've posted (following what I've typeset above) is your work, or if it's something else. Thank you!

 

[GHJ]

Not really... My guess is that the exercise is meant to be as follows:


However, no values seem to have been provided for A and n...? Also, the above is just an algebra "evaluation" exercise, not a graduate-school "Advanced Math" problem, which adds to the confusion.

Kindly please reply with the full and exact text of the exercise, including the complete instructions. Also, please specify if what you've posted (following what I've typeset above) is your work, or if it's something else. Thank you!

The A is supposed to be 1 other than that the exercise that you wrote was correct, sorry for my sloppy handwritting. The value is only provided for m = 2.25 and there is none for n.
And yes it's my work, I was just doing some aditional tasks from my math book and when I finished it, I realised that I've gotten a wrong anwser.

 

[stapel]

The A is supposed to be 1 other than that the exercise that you wrote was correct

Okay; I'll move this to an appropriate category.

The value is only provided for m = 2.25 and there is none for n.

Well, then you can't evaluate. Sorry.

 

[Deleted member 4993]

Upon lot of squinting - I think the expression is

\(\displaystyle \displaystyle{(1-\sqrt{m})^2 - (1+\sqrt{m})^2 - \frac{4(m - \sqrt{mn})}{\sqrt{m} - \sqrt{n}}}\)

First two terms can be simplified easily to -4√m.

The fraction term can be simplified also to 4√m

and continue

 

[Ishuda]

Upon lot of squinting - I think the expression is

\(\displaystyle \displaystyle{(1-\sqrt{m})^2 - (1+\sqrt{m})^2 - \frac{4(m - \sqrt{mn})}{\sqrt{m} - \sqrt{n}}}\)

First two terms can be simplified easily to -4√m.

The fraction term can be simplified also to 4√m

and continue

I believe those first two terms are supposed to be in the denominator, i.e. xxx^-2 rather than xxx². If that is the case, the mistake is in the rationalzation of those. When you rationalize the two values you end up with a common denominator of
\(\displaystyle (1 - \sqrt{m})^2 (1 + \sqrt{m})^2 = [ (1 - \sqrt{m}) (1 + \sqrt{m})]^2 = (1-m)^2\)

I believe the OP has 1 - m² instead.