Question

The number of integral values of m for which the x-coordinate of the point of intersection of the lines 3x + 4y = 9 and y = mx + 1 is also an integer is

(A)  2

(B)  0 

(C)  4 

(D)  1

Answer 1

Correct option  (A)  2

Explanation :

Solving the given equations, the x-coordinate of their point of intersection is

5/3 + 4m = -5, -1

when m = -1 and 2, respectively. That is for m = -1 and  -2, the x-coordinate is also an integer. Hence, the number of integral values is 2.