Question

What is the equation of a line that is perpendicular to this line and goes through the

given point?
y = 3x + 2 (3,-4)

Answer 1

x + 3y + 9 = 0

Explanation:

y=3x + 2

Coefficient of x = 3

Gradient (m) of line y= 3x + 2 is 3

Since the line passing through point

(3,-4) is perpendicular to line y=3x + 2

hence gradient (m) of the line is -1/3;

And hence it equation is given as;

y - y1 = m(x - x1)

y - (-4) = -1/3(x - 3)

multiplying through by 3;

3 × y + 3 × 4 = 3 × -1/3(x - 3)

3y + 12 = -1(x - 3)

3y + 12 = -x + 3

x + 3y + 12 - 3 = 0

x + 3y + 9 = 0