Question

The equation of the locus of all points equidistant from the point (4,2) and the x-axis, is.

• A. $x^{2} + 8x + 4y - 20 = 0$
• B. $x^{2} - 8x - 4y + 20 = 0$
• C. $y^{2} - 4y - 8x + 20 = 0$
• D. None of these

Answer 1

Answer: (B)

$x^{2} - 8x - 4y + 20 = 0$

Answer 2

$( x - 4 ) ^ { 2 } + ( y - 2 ) ^ { 2 } = y ^ { 2 } \Rightarrow x ^ { 2 } - 8 x - 4 y + 20 = 0$.