Thread: Find Equation of Parallel and Perpendicular Lines

Find an equation of the following parallel and perpendicular lines.

A.) The line parallel to and passing through

B.) The line perpendicular to passing through

Is there a specific formula I can use to to solve these?

Originally Posted by larry21

Find an equation of the following parallel and perpendicular lines.

A.) The line parallel to and passing through

B.) The line perpendicular to passing through

Is there a specific formula I can use to to solve these?

The equation of a line passing through a point is given by:



where m is the slope.

Now, two lines are parallel if their slopes are equal.

and two lines are perpendicular if the product of their slopes is -1.

Originally Posted by harish21

For reference, this equation is known as the point-slope equation.

1)required line is parallel to x+3=0 and passes through (-6,-7)
equation of such line will be x=c. since it passes through (-6,-7)
-6=c or
x=-6
x+6=0
[NOTE: line x+k=0 is perpendicular to x axis so any line parallel to it must also be perpendicular to x axis and in the form x+k=0]

2) line perpendicular to y-4=0 will be in the form x=c.
since it passes through(-1,6)
we have -1=c
or c=-1
x=-1
x+1=0