Function f(x) = ax^{3} + bx − 1, where a and b are constants. In addition, f(2) = 3. Find the value of f(−2).

f(2) = -8a -2b - 1; f2) = 3 => -8a -2b - 1 = 3 => 8a + 2b = -4; f(2) = 8a + 2b - 1 = -4 -1 =  -5 => f(2) = -5;