Find the equation of line parallel to the y-axis and drawn through the point of intersection of x – 7y + 5 = 0 and 3x + y – 7 = 0
The equation of any line through the point of intersection of the given lines is of the form
x - 7y + 5 + k(3x + y - 7) = 0
i.e., (1 + 3k)x + (k - 7)y + 5 - 7k = 0 ... (1)
If this line is parallel to y-axis, then the coefficient of y should be zero, i.e.,
k - 7 = 0 ⇒ k = 7
Substituting this value of k in equation (1), we get
22x - 44 = 0
x - 2 = 0
Therefore, the required equation is x - 2 = 0.