1. + 2.5 Writing equations of lines Objective: Write linear equations.

2. + Writing an equation of a line Slope-Intercept Form: given the slope m and the y-intercept b, use slope-intercept form: y = mx+b Point-Slope Form: given the slope m and a point (x 1,y 1 ), use point- slope form: y-y 1 = m(x-x 1 )

3. + Examples Write an equation of the line given slope and y-intercept. 1. m=3, b=1 2. m= -2, b= -4 3. m= ½, b= -5

4. + Write the equation of a line when given a graph.

5. + Examples Write an equation of the line shown. y = __________y = ___________y = ___________

6. + Point-Slope Form

7. + examples Write an equation of the line that passes through the given point and as the given slope. Write your equation in slope- intercept form. 1. (4,2), m= -1/4 2. (-1,3), m= 2 3. (4,-5), m= -3

8. + Examples 4. (-2,4), m=5 5. (-3,-3), m= 2/3

9. +

10. + Write equations of parallel lines Write an equation of the line that passes through (-1,4) and is parallel to the line y = -2x + 5

11. + Write equations of perpendicular lines Write an equation of the line that passes through (-1,4) and is perpendicular to the line y = -2x + 5

12. + Write an equation of the line described. 1. Passes through (-6,-5); parallel to y = -x + 2 2. Passes through (-6, -5); perpendicular to y = -x + 2

13. + Write an equation of the line described 1. Passes through (-2,3); parallel to y =4x – 1 2. Passes through (-2,3); perpendicular to y=4x – 1

14. + Write a linear Model In 1995 there were only 6 California condors living in the wild (all in California). In 2006 there were 138 California condors living in the wild (in California, Arizona, and Mexico). Write a linear model that represents the number of California condors living in the wild between 1995 and 2006.