Consider the following values of x :
1. 2, 2. 4,
3.
Which of the above values of x is/are the solution(s) of the equation
3 only
2 and 3 only
1 and 4 only
4 only
The angle between the two lines lx + my + n = 0 and l'x + m'y + n' - 0 is given by . What is equal to ?