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