SOLUTION: find the value for k so that 9m^2-kn^2 will have the factors 3m+7n and 3m-7n

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Question 90081: find the value for k so that 9m^2-kn^2 will have the factors 3m+7n and 3m-7n
Found 2 solutions by malakumar_kos@yahoo.com, kamallohia:
Answer by malakumar_kos@yahoo.com(315) About Me  (Show Source):
You can put this solution on YOUR website!

find the value for k so that 9m^2-kn^2 will have the factors 3m+7n and 3m-7n
If (3m+7n) and (3m-7n) are the factors then (3m+7n)*(3m-7n)
= (3m)^2 - (7n)^
= 9m^2 - 49n^2
Therefore 9m^2- kn^2 = 9m^2- 49n^2
hence k = 49

Answer by kamallohia(18) About Me  (Show Source):
You can put this solution on YOUR website!
find the value for k so that 9m^2-kn^2 will have the factors 3m+7n and 3m-7n
Now factorize 9m^2-kn^2 and equate the factors with given factors as follows
9m^2-kn^2 = (3*m-n*k^0.5)(3*m+n*k^0.5)
equating with given factors we get
k^0.5=7 =>k=49.
Hope this is clear.
Kamal Lohia