To find the first four terms of the sequence f(n) = (n-1)(n-2), we can simply substitute the first four positive integers (1, 2, 3, and 4) into the formula:
f(1) = (1-1)(1-2) = 0(−1) = 0
f(2) = (2-1)(2-2) = 1(0) = 0
f(3) = (3-1)(3-2) = 2(1) = 2
f(4) = (4-1)(4-2) = 3(2) = 6
Therefore, the first four terms of the sequence f(n) = (n-1)(n-2) are 0, 0, 2, and 6.