If a + b = 8 and a^2 + b^2 = 12, then the value of a^3 + b^3 is:

ab = [(a + b)² − (a² + b²)]/2 = (64 − 12)/2 = 26. a³ + b³ = (a + b)³ − 3ab(a + b) = 512 − 3 × 26 × 8 = 512 − 624 = −112.