[INST] Given the square of an integer x is 1521, what is the value of (x+1)(x-1)?/n [/INST]  ###Response: Using the difference of squares factorization, we see that (x+1)(x-1) = x^2-1. Since we're given x^2= 1521, we can easily compute x^2-1 = 1521-1 = 1520.