SOLUTION: Please help this is confusing to me. Find a value for k so tha 9m^2 - kn^2 will have the factors 3m + 7n and 3m

SOLUTION: Please help this is confusing to me. Find a value for k so tha 9m^2 - kn^2 will have the factors 3m + 7n and 3m - 7n.

Question 77222: Please help this is confusing to me.
Find a value for k so tha 9m^2 - kn^2 will have the factors 3m + 7n and 3m - 7n.
Found 2 solutions by THANApHD, jim_thompson5910:
Answer by THANApHD(104) (Show Source): You can put this solution on YOUR website!
9m^2 - kn^2 can be written in factor form as like this
9m^2 - kn^2 = (3m+7n)(3m-7n)
9m^2 - kn^2 = 9m^2 - 49n^2
so
kn^2 = 49n^2
k =49
Answer by jim_thompson5910(35256) (Show Source): You can put this solution on YOUR website!
If you foil you get

Notice the middle terms cancel

So we have which is equal to so in other words:

Subtract from both sides
Divide both sides by
Divide both sides by -1
So we get

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