Question 76260: Find a value for k so that 9m(squared)- kn(squared) will have the factors 3m + 7n and 3m - 7n.
thanks Answer by wodkit02(9) (Show Source):
You can put this solution on YOUR website! If you want the expression to have the factors of (3m-7n) and (3m+7n), you must multiply those factors together to see if it has the form 9m^2-kn^2.
Using the FOIL method, we get:
(3m-7n)(3m+7n)
9m^2+10m-10m-49n^2
9m^2-49n^2
Now we compare this result to the expression with the k-value in it:
9m^2-kn^2 = 9m^2-49n^2
thus k = 49
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