Problem Solving (PS) | Re: The lines with equations ax - 2y = c and 2x + by = -c are perpendicula

Since both the lines are perpendicular to each other, the product of their slopes should be -1.
The slope of line ax-2y=c is (a/2) and the slope of line 2x+by = -c is (-2/b). Therefore, (a/2)*(-2/b) = -1.
Solving this equation, we find that a=b.
The second condition of the problem states that both the lines intersect at (1,-5) which also implies that this point falls on both the lines.
In line ax-2y=c, replacing x with 1 and y with -5 and also 'a' with 'b' (derived from above equation), we get
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