Find the equation of the line with slope -2 and passing through the point of intersection of the lines 3x+y=0 and x-2y+7=0 and parallel to the line x+3y-1=0.
Please show the steps and I wanna know if the slope of the line x+3y-1=0 equals to the slope of the line with slope -2, since they are parallel.
Thanks.
F.4 maths - coordinates
2009-07-27 11:47 pm
回答 (2)
2009-07-28 3:25 am
✔ 最佳答案
Forget about the line x + 3y - 1 = 0Equation of the family of line passing the intersecting point is
(x - 2y + 7) + k(3x + y) = 0
x - 2y + 7 + 3kx + ky = 0
(1 + 3k)x + (k - 2)y + 7 = 0
its slope = -(1 + 3k)/(k - 2) = (1 + 3k)/(2 - k).
For slope = - 2
that is (1 + 3k)/(2 - k) = -2
1 + 3k = -4 + 2k
k = - 5
so the line is x - 2y + 7 - 15x - 5y = 0
14x + 7y = 7
or 2x + y = 1.
It is not parallel to x + 3y - 1 = 0, because slope of this line is - 3.
2009-07-27 11:56 pm
The question is contradictory.
The slope of x + 3y - 1 = 0 is -1/3. It is not equal to -2.
The slope of x + 3y - 1 = 0 is -1/3. It is not equal to -2.
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