Question

Question 6 Find the equation of the line parallel to y-axis and drawn through the point of intersection of the lines x – 7y + 5 = 0 and 3x + y = 0.

Class X1 - Maths -Straight Lines Page 233

Answer 1

slope of line parallel to Y-axis is 1/0

Here , equation of lines are
x - 7y + 5 = 0------------(1)
3x + y = 0 ----------------(2)

solve equations (1) and (2) for finding point of intersection of these two lines .

x - 7y + 5 + 21x + 7y = 0
22x + 5 = 0
x = -5/22 , put it in equation (2)
y = -3x = 15/22
hence, the point is ( -5/22, 15/22)

now, equation of required line by using
y - y1 = m(x - x1)
(y - 15/22) = 1/0(x + 5/22)
0 = x + 5/22
22x + 5 = 0

hence, required line: 22x + 5 = 0