find the equation

Question

find the equation of the line that passes through (1,-2) and is perpendicular to the line x+5y=2015

Answer 1

First let's convert the line we know into slope-intercept form:

x + 5y = 2015

5y = -x + 2015

y = ^-1/₅x + 403

 

We now know the slope of the first line. The slope of a perpendicular line is the negative reciprocal, which for -1/5 is 5.

We have a slope, we have a point, so we can use point-slope form:

y - y₁ = m(x -x₁)

y - -2 = 5(x - 1)

y + 2 = 5(x - 1)

 

If you desire to convert it to slope-intercept form, you can distribute the 5 on the x side, and then move that 2 on the y side by subtracting 2 to both sides.