Point-slope formula

Point-slope formula

y - y1 = m(x - x1)

This formula helps to determine the equation of a line given a point (x1, y1) and the slope, m, of the line.

Example 1:

A line contains the point (5, 3) and has a slope of 2. Find the equation of the line.

Step 1:

Identify your point and slope.

(x1, y1) = (5, 3)

m = 2

Step 2:

Substitute and solve for y.

(y - 3) = 2(x - 5)     Substitute into formula.

y - 3 = 2x - 10     Distribute.

y - 3 + 3 = 2x - 10 + 3     Add 3 to both sides.

y = 2x - 7   Answer!

Example 2:

Find the equation of the line containing (-4, 6) with a slope of -3.

Step 1:

Identify point and slope.

(x1, y1) = (-4, 6)

m = -3

Step 2:

Substitute and solve for y.

y - 6 = -3(x - -4)     Substitute.

y - 6 = -3x - 12     Distribute.

y - 6 + 6 = -3x - 12 + 6     Add 6 to both sides.

y = -3x - 6     Answer

Related Links:






Educational Videos