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. [basically changing the sign (+/-) and flipping the fraction/or switching the numerator and the denominator]
For example:
m = 2 or [tex]\frac{2}{1}[/tex]
Perpendicular line's slope = [tex]-\frac{1}{2}[/tex]
m = [tex]-\frac{1}{4}[/tex]
Perpendicular line's slope = [tex]\frac{4}{1}[/tex] or 4
Since you know the slope of the line is:
y = -3/4x + 5
m = [tex]-\frac{3}{4}[/tex]
The perpendicular line's slope is [tex]\frac{4}{3}[/tex], so plug it into the equation
y = mx + b
[tex]y=\frac{4}{3} x+b[/tex] To find b, plug in the point (-3, -3) into the equation
[tex]-3=\frac{4}{3} (-3)+b[/tex]
-3 = -4 + b Add 4 on both sides to get "b" by itself
1 = b
The y-intercept is 1
