71.
A line passing through the origin perpendicularly cuts the line 3x - 2y = 6 at point M. Find the co-ordinates of M.

72.
What would be the equation of the line, which intercepts x-axis at -5 and is perpendicular to the line y = 2x + 3?

73.
The length of the portion of the straight line 3x + 4y = 12 intercepted between the axes is:

74.
P(4, 2) and R(-2, 0) are vertices of a rhombus PQRS. What is the equation of diagonal QS?

75.
What is the equation of the line perpendicular to the line 2x + 3y = -6 and having Y-intercept 3?

76.
The line passing through the point (5, a) and point (4, 3) is perpendicular to the line x - 6y = 8. What is the value of 'a'?

77.
What is the equation of the line which intercepts x-axis and y-axis at $$\frac{3}{4}$$ and $$ - \frac{2}{3}$$ respectively?

78.
The graphs of the equations 3x + y - 5 = 0 and 2x - y - 5 = 0 intersect at the point P(α, β). What is the value of (3α + β)?

79.
The line passing through point (-3, 1) and point (x, 5) is parallel to the line passing through point (-2, -1) and point (6, 3). What is the value of x?

80.
Slope of the line AB is $$ - \frac{2}{3}.$$  Co-ordinates of points A and B are (x, -3) and (5, 2) respectively. What is the value of x?