Question

Find the equation of the straight line which passes through the point (1, – 2) and cuts off equal intercepts from axes.

Answer 1

Intercept form of straight-line `x/a + y/b` = 1

Where a and b are the intercepts on the axis

Given that a = b

∴ `x/a + y/a` = 1   ....(i)

If equation (i) passes through the point (1, – 2), we get

`1/a - 2/a` = 1

⇒ `-1/a` = 1

⇒ a = – 1

So, equation of the straight line is

`x/(-1) + y/(-1)` = 1

⇒ x + y = – 1

⇒ x + y + 1 = 0

Hence, the required equation is x + y + 1 = 0.