# 4.5 Point-Slope form of a linear equation 4.5 Point-Slope form of a linear equation y y1 m( x x1 ) If a line passes through (2, -4) and has a slope of 5, write the point-slope form of the equation of the line. y ( 4) 5( x 2) y 4 5( x 2)

Try this one If a line passes through (-2,0) and has a slope of -3/2, write the point-slope form of the equation of the line. y y1 m( x x1 ) 3 y 0 ( x 2) 2

3 y ( x 2) 2 Horizontal & Vertical Lines Horizontal Lines Slope = 0 The equation of the line is y = # Point-slope form: y - # = 0

Vertical Lines Slope = undefined The equation of the line is x = # There is no point-slope form Standard Form of a Linear Equation Ax + By = C A, B, and C are integers (numbers). A is not a fraction, decimal, or negative.

A or B can be zero but not both. Standard Form: Ax + By = C Given: y + 4 = 5(x 2) Write it in Standard Form y 4 5( x 2) y 4 5 x 10 y 5 x 14 5 x y 14

5 x y 14 Distribute Subtract 4 from both sides Subtract 5x Change all signs so A is not negative. Write it in slope-intercept form Given:

y 3 6( x 1) y 3 6 x 6 y 6 x 9 Distribute Subtract 3 Try These ~ Page 223 #1, 5, 8

1. y 3 = -2(x -1) 5. 3x + 4y = -9 8. y = -2/3x + 1