solve equation 724 = 15(a^5/2) + 12
724 = 15(a^5/2) + 12 subtract 12 from both sides
712 = 15a^(5/2) divide both sides by 15
712 / 15 = a^(5/2) take each side to the 2/5 power
[ 712/15 ] ^(2/5) = a ≈ 4.6833