Question

Find the equation of the line which passes through (-2,1) and which is perpendicular

Answer 1

A line that is perpendicular to a line with slope m has slope -1/m which is the opposite reciprocal of the original slope.

In this case the original line in standard form is

2x-4y=-8

transform this into slop intercept form

-4y=-2x-8

4y=2x+8

y=(1/2)x+2

The slope of this original line is 1/2 therefore the perpendicular line will have slope -2

y'=2x'+b

then substitute in the order pair (x',y')

1=2(-2)+b

b=5

Therefore equation of line is

y=2x+5

The graph is just following this equation!

If you have any questions about my explanation please ask I will answer them to the best of my ability.