Q.the image of the pt.(3,8) in the line x+3y=7.
options a.(1,4)
b.(4,1) c.(-1,-4)
d.(-4,-1)
Q.the image of the pt.(3,8) in the line x+3y=7.
options a.(1,4)
b.(4,1) c.(-1,-4)
d.(-4,-1)
KAMAL RAWAT , 14 Years ago
Grade 12
Analytical Geometry> how to solve this question....
1 Answers
Rup Chitrak
[Ans: (c)]
Learn a formula
Reflection of a point P(x1,y1) in ax+by+c=0 is Q(h,k) where
(h-x1)/a = (k-y1)/b = {-2(ax1+by1+c)}/(a2+b2)
now apply this formula...
(h-3)/1 = -40/10 = -4
or, h=-1
(k-8)/3 = -40/10 = -4
or, k = -4.
thus point of reflection is (-1,-4).
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