Given, numbers a, b, c are in AP ∴ 2b = a + c ... (i) Now, the given straight line,
x
a
+
y
b
+
1
c
= 0 ⇒
x
a
+
y
b
+ = −
1
c
⇒
x
(
a
−c
)
+
y
(−
b
c
)
= 1 ... (ii) By using condition (i), we cannot determine that line (ii) passes through from which point. So we can say that given condition for question is wrong for concluding a definite result.