If \(x+y=\frac{7}{13} (and )x-y=\frac{1}{91},\) what is the value of \(x^2-y^2\)? Express your answer as a common fraction.
x + y = 7/13
x - y = 1/91
Note that x^2 - y^2 can be factored as ( x + y) (x - y) .....substituting....we have that
x^2 - y^2 = ( 7/13) ( 1/91) = (7/91) (1/13) = (1/13)(1/13) = 1 / 169
+385 
