Question
Question: For all values of a and b the lines (a + 2b)x + (a – b)y + (a + 5b) = 0 passes through the point...
For all values of a and b the lines
(a + 2b)x + (a – b)y + (a + 5b) = 0 passes through the point
A
(–1, 2)
B
(2, –1)
C
(–2, 1)
D
(1, –2)
Answer
(–2, 1)
Explanation
Solution
a(x + y + 1) + b(2x –y + 5) = 0
(x + y +1) + 
(2x – y + 5) = 0
(x + y +1) + l (2x – y + 5) = 0
passes through the intersection
points x + y + 1 = 0
2x – y + 5 = 0
x = –2, y = 1