不等式ax2+bx-2>0的解集是{x│x1/3}则ab的值是
满足 x1x2 = -2/a = -1/6
a = 12
x1+x2 = -b/a = -1/2 + 1/3 = -1/6
b = a/6 = 12/6 =2
ab =12 x 2 =24