Lesson 13, Section 2.4A Slopes and Graphs of Vertical or Horizontal Lines1. Slope of a horizontal line ),(1yx),(2yx#012xxyymZero divided by any number is zero.The slope of a horizontal line is zero.2. Graph of a horizontal lineGraph 4)( yxfx y -4 -4 -4 -4 If a line is of the form, byxf )(, then the line is horizontal with a y-intercept at (0, b) and the slope of this line is zero.3. Slope of a vertical line0#12xxyymA fraction with a 0 denominator is undefined.The slope of a vertical line is undefined.4. Graph of a vertical line Graph x + 2 = 4x 2 2 2 y yx),(1yx),(2yxyxIf a line is of the form, ax , then the line is vertical with an x-intercept at (a, 0) and the slope of this line isundefined.Find the slope and graph ofeach.Ex 11043 xEx 232yB InterceptsAn ordered pair (0, b ) is the y-intercept of a line and anordered pair ( a , 0) is the x -intercept of a line. Notice:One of the coordinates is zero. Lines are easilygraphed using the intercepts.Find the intercepts and graph.Ex 3141 xyEx 41834 yxEx 523)( xxfC ApplicationsMany real life situations can be represented as a linear function (usually a function of time). The initial amount or number is the b and the rate of change is the m.Ex 6 Molly Jones agrees to pay $8000 down payment plus $350 a month to pay for a car. a) Write a linear function to illustrate her total payments as a function of the number of months.Use this function to answers parts (b) and (c).b) How much has Molly paid on the car in 5 months from purchase?c) If the total (including any interest or fees) that Molly needs to pay is $20,600, how many months will it take to pay off the car?Ex 7 One plan from Jitterbug Phones charges a customer $140 for a phone and fees to open an account plus payments of $30 a month (for 30 minutes per month). a) Write a cost function to represent the total paid for this plan from the beginning.Use your function to find or predict the following.b) How much has a customer with this plan paid in 9 months?c) How long will it take before the customer has paid $1640?A Linear Function is one of the formbmxy . Notice that the x and y are only 1st powers. Any other type of function is called a non-linear function.Ex 8 Identify each equation or function as linear or non-linear.a)943 yxb)43)( ttgc)32)( xxfd)xxy 23e)105 yf)2)(
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