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Question 931491: Please assist,
Write the equation of a line perpendicular to the given line but passing through the given point.
y = -4x - 5; point (0, -1)
Answer by KMST(5328)   (Show Source):
You can put this solution on YOUR website! The slope of the line represented by  is  .
The slope of a line perpendicular to a line of slope  } is  ,
so the slope of the line you are looking for is
 .
The x-coordinate of the point the line passes through is zero, meaning that the point is on the y-axis.
In other words that point is the y-intercept of the line.
The equation of a line can be written in the slope-intercept form as
 when the slope is  and the y-intercept is  ,
so the equation you are looking for is
NOTE: For this problem, the point given "happens to be" the y-intercept.
More generally:
A line of slope , passing through a point 
can be represented by the equation  ,
and that is called a point-slope form of the equation.
So, the line you are looking for, passing through (0,-1) can be represented by the equation
 <---> 
The equation above is one of the infinite number of equations for the line you are looking for.
The more popular, one and only, slope-intercept form is the form that you find when you "solve for y" :
<--->  .
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