Wetzel

Math 155

7.2 – Linear Functions and Their Graphs

Linear Equations with Two Variables –

·        Standard Form –

                  ax + by = c

·        Infinitely Many Solutions

Ex. :

Determine if the given point is a solution to the equation.

1.)  (3, -3),  4x – 3y = 21                                 2.)  (5, -2),  -x + 7y = -9

Intercepts –

            x – intercept:     (x, 0)

            y – intercept:     (0 , y)

Ex.:      Find the intercepts.

3.)  2x – 5y = 10                                  4.)  y = -⅓x + 2

Slope, (m) –

            Definition:

            Slopes of Lines:

            Finding slope of a line given two point -            

                        m =

Ex.:  Find the slope of the line passing through the following points.

5.)  (3, 7) and (0, 2)                 6.)  (-5, 0) and (-1, -6)             7.)  (2, 0) and (2, 9)

Slope - Intercept Form

                        y = mx + b

                        where m = slope and b = y-intercept

Ex.:

Find the slope and y-intercept of each equation.

8.)  y = 5x +3               9.)  y = -⅓x-1              10.)  y = 7x      11.)  8x - 6y =12

Write an equation for a line with the given slope and y-intercept.

12.)  slope = -4 and y-intercept is at (0, -5).

HW:  p.388 #1-29odd