Given that x+y=\frac7{10} and x-y=\frac5{14}, find the value of x^2-y^2, expressed as a common fraction.
Solving the equations, you get x = 18/35 and y = 1/7, so x^2 - y^2 = (18/35)^2 - (1/7)^2 = 299/1225.