Write a pair of linear equations which has the unique solution x = - 1, y = 3.how many such pairs can you write?

As value of x = - 1 and y = 3 should be solution of a linear equations.
So such equation can be : x + y - 2 = 0
or 3x + y = 0

As x = - 1 and y = 3 are coordinates of a point in a plane and we know that we can draw infinite lines through a point in a plane so there are infinitely many equations are possible whose solution is satisfied by x = - 1 and y = 3