Linear Equation (Point slope form)

When we know the slope and one point which is not the y-intercept, we can write the equation in point-slope form.

Equations in point-slope form look like this:
Y - k = M(X - h)
where M is the slope of the line and (h, k) is a point on the line (any point works).

Example : Write an equation of the line which passes through (3, 4) and has slope m = 5
h = 3 and k = 4.
Y - k = M(X - h) point-slope form
y - 4 = 5(x - 3) (use distributive property a(b+c) = a*b+a*c, 5 ( x - 3 ) = 5 x - 15)
Y – 4 = 5x – 15 (adding 4 to both sides)
Y = 5x -11

Practice:
Write an equation of the line which passes through (- 3, - 7) and has slope m = 3
Write an equation of the line which passes through (- 1, - 1) and has slope m = 2
Write an equation of the line which passes through (1, 2) and has slope m = -3

Answers:
y = 3x + 8
y = 2x + 1
y = -3x + 5