Explanation

(b)
Let the image of reflection of the origin with reference to the line $4x + 3y - 25 = 0$ is $(h,\ k)$
$\therefore\frac{h - 0}{4} = \frac{k - 0}{3} = \frac{- 2(0 + 0 - 25)}{16 + 9} = 2$
$\Rightarrow \ \frac{h}{4} = 2\ \ \Rightarrow \ h = 8$
$and\ \frac{k}{3} = 2\ \Rightarrow \ k = 6$
$\therefore$ Required point is (8, 6)