Q. The equation of the line passing through the origin and the point of intersection of the lines $\frac{x}{a} + \frac{y}{b} = 1$ and $\frac{x}{b} + \frac{y}{a} = 1$ is
A) $bx - ay = 0$
B) $x + y = 0$
C) $ax - by = 0$
D) $x - y = 0$
Explanation
(d)
$Point\ of\ intersection\ of\ \frac{x}{a} + \frac{y}{b} = 1\ and\$
$\frac{x}{b} + \frac{y}{a} = 1\ is\ \left( \frac{ab}{a + b},\frac{ab}{a + b} \right)$
$\therefore Equation\ of\ line\ joining\ (0,\ 0)\ and$
$\left( \frac{ab}{a + b},\frac{ab}{a + b} \right)\ is\ x = y\ ie,\ x - y = 0$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.