Find the equation? find the equation of a line through
the point (-1,9) an perpendicular to 2x-4y =7
how do you find the equation of a line?
We need the given equation in slope/intercept form.
2x - 4y = 7
-4y = -2x + 7
y = (-2/-4)x + 7/-2
y = 1/2 x - 3/5
A line perpendicular to this line has a slope that
is the negative reciprocal of this line's slope.
The negative reciprocal of 1/2 is -2/1, that is, -2.
The new equation is y = -2x + b. We need to calculate
the y-intercept, b, for this new line.
y = -2x + b
b = y + 2x
Plug in the x and y values of the given point.
b = y + 2x
b = 9 + 2(-1)
b = 9 - 2
b = 7
Now, we can give the complete equation:
y = -2x + 7