(a) | a | = | b |
The equation of line AB, i.e., ax + by + c = 0 in intercept form is ax + by = – c
⇒ \(\frac{x}{\big(-\frac{c}{a}\big)}\) + \(\frac{x}{\big(-\frac{c}{b}\big)}\) = 1
Δ AOB is isosceles Δ if OA = OB, i.e., x-intercept = y – intercept
⇒ \(\frac{-c}{a}\) = \(\frac{-c}{a}\) ⇒ \(\frac{1}{a}\) = \(\frac{1}{a}\) ⇒ | a | = | b |.