Question

What is the slope of a line that is perpendicular to 6x + 3y = –9?

Answer 1

6x + 3y = -9
3y = -6x - 9
y = -2x - 4.5

slope (m1) of this line is -2

slope of the perpendicular line,
m2 = - (1/m1)
m2 = - (1 / -2)
m2 = 1/2

Answer 2

6 x + 3 y = -9
3 y = - 6 x - 9   / : 3  ( divide both sides by 3 )
y = - 2 x - 3
m 1 = -2
Slope of the perpendicular line:
m 2 = - 1 / ( - 2 ) 
m 2 = 0.5