b) the coordinates of the point of contace for each tangent found in (a)
更新1:
Could you give me more detailed steps from (4c + 18)^2 - 20(c^2 + 6c - 2) = 0 to c^2 - 6c - 91 = 0
更新2:
From x^2 + 2x + 1 = 0 to x = -1 then y = -5. So, contact point (-1, -5) How to know that x = -1 then y = -5 ?
更新3:
How to know x = -1 ? 我可能睇miss左D野, 希望您耐心指導^^
更新4:
http://hk.knowledge.yahoo.com/question/question?qid=7011012401441 唔該答埋呢到, 我會比哂最佳您