Question

Consider the linear equations

7x – 14y = 9 , 5x – 10y = a
For what value of a, the pair of linear equations will have a unique solution

Answer 1

trick question --

since the slopes are the same, they are either
(a) parallel (no solutions)
(b) the same line (infinitely many solutions)

There is a unique solution (point of intersection) when the slopes are different.