6.已知两定点A(−3,0)A(-3,0)A(−3,0),B(3,0)B(3,0)B(3,0),过动点PPP的两直线PAPAPA和PBPBPB的斜率之积为−89-\frac{8}{9}−98.设动点PPP的轨迹为CCC.(1)求曲线CCC的方程;(2)设F1(−1,0)F_{1}(-1,0)F1(−1,0),过F1F_{1}F1的直线lll交曲线CCC于MMM、NNN两点(不与AAA、BBB重合).设直线AMAMAM与BNBNBN的斜率分别为k1k_{1}k1,k2k_{2}k2,证明k1k2\frac{k_1}{k_2}k2k1为定值.