362,136 views
10 votes
10 votes
The equation of the line is perpendicular to y= 1/2X +3 and passes through -2 and 5 in slope intercept form

The equation of the line is perpendicular to y= 1/2X +3 and passes through -2 and-example-1
User Melanie
by
2.6k points

1 Answer

22 votes
22 votes
Step-by-step explanation

The slope-intercept equation of a line has the form


y=m\cdot x+b,

where m is the slope of the line and b is its y-intercept.

Now, there is a very interesting relationship between the slopes (m_1 and m_2) of perpendicular lines:


m_1=-(1)/(m_2)\text{.}

Looking at the given equation, we can say that its slope is 1/2. Then,


m=-(1)/((1)/(2))=-2.

Then, our desired equation becomes


y=-2x+b\text{.}

Now, we know that our line passes through (-2,5). This means that


5=-2\cdot(-2)+b\text{.}

Solving this equation for b, we get


\begin{gathered} 5=4+b, \\ 4+b=5, \\ b=5-4, \\ b=1. \end{gathered}

Answer

The desired line has equation


y=-2x+1.

User Peter Rakmanyi
by
3.0k points