Equation of radical axis of circles 2{x^2} + 2{y^2} - 7x = 0 and {x^2} + {y^2} - 4y - 7 = 0 is

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10-1.Circle and System of Circles

medium

The equation of radical axis of the circles $2{x^2} + 2{y^2} - 7x = 0$ and ${x^2} + {y^2} - 4y - 7 = 0$ is

A

$7x + 8y + 14 = 0$

B

$7x - 8y + 14 = 0$

C

$7x - 8y - 14 = 0$

D

None of these

Solution

(c) Equation of radical axis, ${S_1} – {S_2} = 0$

i.e., $(2{x^2} + 2{y^2} – 7x) – (2{x^2} + 2{y^2} – 8y – 14) = 0$

$ \Rightarrow – 7x + 8y + 14 = 0$,

$\therefore \;7x – 8y – 14 = 0$.

Standard 11

Mathematics

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