Question 10The lines $L$ and $K$ are symmetric to each other with respect to the line $y=x.$ If the equation of line $L$ is $y=ax+b$ with $a\ne0$ and $b\ne0,$ then the equation of $K$ is $y=$$\frac1a x+b$$-\frac1a x+b$$-\frac1a x-\frac ba$$\frac1a x+\frac ba$$\frac1a x-\frac ba$