The equation of line CD is y = 3x - 3. Write an equation of a line perpendicular to line CD in slope-intercept form that contains point (3, 1). (5 points)
y = 3x + 0
y = 3x - 8
Tl
Tom

Slope-intercept form:  y = mx + b

(m is the slope, b is the y-intercept or the y value when x = 0 --> (0, y) or the point where the line crosses through the y-axis)

For lines to be perpendicular, their slopes have to be negative reciprocals of each other. (flip the sign +/- and the fraction/switch the numerator and the denominator)

For example:

Slope = -2 or

Perpendicular line's slope =     (flip the sign from - to +, and flip the fraction)

Slope =

Perpendicular line's slope =  or -3    (flip the sign from + to -, flip fraction)

y = 3x - 3   The slope is 3, so the perpendicular line's slope is .

Now that you know the slope, substitute/plug it into the equation:

y = mx + b

   To find b, plug in the point (3, 1) into the equation, then isolate/get the variable "b" by itself

1 = -1 + b   Add 1 on both sides to get "b" by itself

1 + 1 = -1 + 1 + b

2 = b