Let the required point be (x,y). Then
x<0,y<0,x=3y
d2=(x−(−2)2+(y−4)2=102
(3y+2)2+(y−4)2=100
9y2+12y+4+y2−8y+16−100=0
10y2+4y−80=0
5y2+2y−40=0
D=(2)2−4(5)(−40)=804
y=2(5)−2±804=5−1±201 Since y<0, we take y=5−1−201.
x=3(5−1−201)
Point (−53+3201,−51+201)
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