Example Problems Answers

1.Give the domain and range for the following relation and tell whether it is a
     function:    {(3,-2), (5,1), (-4,3), (5,6), (0,8) .
        domain: {-4,0,3,5}        range: {-2,1,3,6,8}
        Is not a function because 5 is mapped to 1 and 6.

2. Find the slope between (4,-5) and (-3,2).

2+5	slope is -1
-3-4

3. Give slope and y-intercept for the line: -8x + 4y = 12
    Solve for y first: 4y = 8x + 12
                               y = 2x + 3        slope is 2 and y-intercept is 3

4. What is the standard form of the line that passes through (-4,8) and has
    slope of -3?    y - 8 = -3(x + 4)
                           y - 8 = -3x - 12
                           3x + y = -4

5. What is the slope-intercept form of the equation of the line that passes
    through (4,1) and (-2,3)   

1 - 3	slope is	-1
4 -(-2)		3

 y - 1 = -⅓(x - 4)
y - 1 = -⅓x + 1⅓
y = -⅓x + 2⅓

6. Write equation of the line that is parallel to y = 7x - 8 and passes through (2,6)

m = 7 then y - 6 = 7(x - 2)
y - 6 = 7x - 14
y = 7x - 8
 

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

m = -¼ then y - 2 = -¼ (x + 1)
y - 2 = -¼ x - ¼
y = -¼ x + 1¾

8. Find slope and y-intercept and use to graph the line 6x + 8y = 16

8y = -6x + 16
y = -¾x + 2    slope is -¾ and y-intercept is 2