Sasha S. answered 01/14/21
Bridging the Gap Between Math Foundations and Passing the EOC
Hello,
For lines to be perpendicular their slope has to have opposite signs and the slopes have to be the reciprocal of one another.
The given slope is 2/3x the perpendicular slope would be: -3/2x
There are two methods to solving: Method 1: Use the Slope Formula Y=MX+b
M = Slope of the Perpendicular line: -3/2x
use (-3,4) for (X,Y)
4 = -3/2(-3) + b - Plug in the X and Y and Simplify
9/2 + b
4 = 9/2 + b Now Solve for b
-9/2 -9/2
4/1 - 9/2 = -1/2
b= -1/2 Final Answer: y= -3/2x -1/2 this line is perpendicular to y=2/3x + 1/3
Method Two using Point Slope Formula
To write the equation use the Point Slope Formula: y-Y1=M(x-X1) Plug in (X1,Y1) using (-3,4)
Plug in M using the Perpendicular slope -3/2x
y-4 =-3/2(x- (-3) be careful watch the( minus and the -3) a negative times a negative creates a positive
y-4= -3/2(x+3) Now distribute
y-4 =-3/2x -9/2
+4 +4
-9/2 + 4/1 = -1/2
Final Answer y= -3/2x - 1/2 This line is perpendicular to y = 2/3x + 1/3 and passes through point (-3,4) when graphed.