Find an equation for the line perpendicular to the line 5x-20y=3 having the same y-intercept as -7x-4y=8
The first equation 5x-20y=3 solved for y=mx+b is `y=1/4x-3/20` Since the equation has a slope (m) of 1/4 the perpendicular slope would be -1/m or -4. So my answer equation has to be y=-4x+b.
The second equation -7x-4y=8 tells me the y-intercept solved for y=mx+b it's `y=-7/4 x-2` b is the y-intercept and it's -2.
So I need a slope (m) of -4, and a y-intercept (b) of -2. That gives me an equation `y=-4x-2`
let us write given equation -7x-4y=8 in intercept form as
y intercept of equation (i) is -2
Rewrite equation 5x-20y=3 ,in slope intercept form
slope of line (ii) is (1/4)
required line to be perpendicular to (ii) ,let slope of required line be m . So
So slope of required line is -4 and intercept is -2
So equation of line will be