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Question
If a, b, c are in A.P., then the straight lines ax + by + c = 0 will always pass through ______.
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Solution
If a, b, c are in A.P., then the straight lines ax + by + c = 0 will always pass through (1, – 2).
Explanation:
Given equation is ax + by + c = 0 .....(i)
Since a, b and c are in A.P.
∴ b = `(a + c)/2`
⇒ a + c = 2b
⇒ a – 2b + c = 0 .....(ii)
Comparing equation (i) with eq. (ii) we get,
x = 1, y = – 2
So, the line will pass through (1, – 2).
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