SOLUTION: Find a value for k so that 9m^2- kn^2 will have the factors 3m + 7n and 3mn -7n. I am confussed can someone lend me some help please. Thanks.

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: Find a value for k so that 9m^2- kn^2 will have the factors 3m + 7n and 3mn -7n. I am confussed can someone lend me some help please. Thanks.      Log On


   

Question 70542This question is from textbook Beginning Algebra
: Find a value for k so that 9m^2- kn^2 will have the factors 3m + 7n and 3mn -7n.
I am confussed can someone lend me some help please. Thanks. This question is from textbook Beginning Algebra

Answer by funmath(2933) About Me  (Show Source):
You can put this solution on YOUR website!
Find a value for k so that 9m^2- kn^2 will have the factors 3m + 7n and 3mn -7n.
The difference of perfect squares factor like this:
highlight%28a%5E2-b%5E2=%28a%2Bb%29%28a-b%29%29
b^2=b*b
so:
kn%5E2=7n%2A7n
kn%5E2=49n%5E2
highlight%28k=49%29
Happy Calculating!!!!