Find the equation of a straight line which is in the family (2x + 5y + 1) + k(3x - y + 7) = 0 but not represented by this equation.
Straight Line
2009-07-20 4:12 am
回答 (1)
2009-07-20 4:21 am
✔ 最佳答案
answer is 3x - y + 7=0 Since when k takes any real value , the family of the straight lines cannot show 3x - y + 7=0 this equation .
Indeed , for the family of the straight lines :
(A1x+B1y+C1)+k(A2x+B2y+C2)=0 ...(*)
The one that cannot be shown in (*) is A2x+B2y+C2=0 , you have to memorize it .
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