直线 ax - 2y - 1 = 0 转化为：y = (a/2)x - 1/2 其斜率是k1 = a/2直线 6x + 4y + b = 0 转化为：y = ( -3/2)x - b/4,其斜率是 k2 = - 3/2要使这两直线平行,k1 = k2 且 - 1/2 ≠ -b/4由k1 = k2得:a/2 = - 3/2 解得：...答案上给的是a=-3,b=2啊 是不是答案错了