Question

Write an equation of a line in slope-intercept form for the

given conditions.
passes through (4, 20) and is perpendicular to the line
y= 4x + 5

Answer 1

Using the general equation formula;
y-y1=m(x-x1)

y1=20 and x1=4
Since the two lines are perpendicular, they have the same gradients
But gradient for y=4x+5 is 4
Therefore m of the equation is 4


Substituting all this into the general formula;

y-20=4(x-4)
y-20=4x-16
y=4x-16+20
y=4x+4