If m + 1/m = 8, what is the value of m^3 + 1/m^3?
Note that $(m + 1/m)^3 = m^3 + 3m + 3/m + 1/m^3 = (m^3 + 1/m^3) + 3(m+1/m)$. So $m^3+1/m^3 = (m+1/m)^3 - 3(m+1/m) =8^3-3*8$
