Question

consider the line x + 3y= -9 What is the slope of a line parallel to this line? What is the slope of a line perpendicular to this line?

Answer 1

Hello ther is a solution :
x+3y = -9
3y =-x-9
y = (-1/3)x-3
1 ) the slope of a line parallel to this line is : (-1/3)
2 ) let ' a ' the slope of a line perpendicular a line: x+3y = -9
I'have (-1/3)× a = -1
a = 3