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Warm up: need calculator to find linear regression equations – use notes if necessary!. Write 2 regression equations :. Life Expectancy at Birth. Y M = .205x -335.186. Y W = .119x – 157.962. Predict the life expectancy for children born in 2015:.
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Warm up: need calculator to find linear regression equations – use notes if necessary! Write 2 regression equations: Life Expectancy at Birth YM = .205x -335.186 YW = .119x – 157.962 Predict the life expectancy for children born in 2015: Find the intersection point to the nearest whole numbers and describe what it represents in this situation. In 2068, the life expectancy is 88 years for both men and women.
3rd day 1 Solve Systems by Substitution, Elimination, and Graphing Review a Regression Equation
Write the two equations with a partner and graph. 1. Write a System and Solve by Graphing and Substitution (Cost is a function of transactions) “Bank of Money” charges 50 cents per transaction and no monthly fee. “Lo-Fee Credit Union” charges a monthly fee of $12 and 15 cents per transaction. System: For 1 month When will the cost be the same? C($) (20,15) 12 3 T 7 42
2. Write a System and Solve Avis charges a flat fee of $100 plus $15 per day to rent a Ford Focus. Hertz charges a flat fee of $30 plus $25 per day for the same car. Find the # of days(d) at which the cost (c) will be the same. System: Same costs? Marker Boards: evens
3. Solve by Substitution ! Systems can have: 1 sol: graphs intersect (Independent) No Solution: Parallel (Inconsistent) Infinite Sol: Same line (Dependent) 4x+2(5x) =7 4x + 10x = 7 14x = 7
4. Solve by Substitution ! Marker Boards: odds 4p+2(2p+1) =8 4p +4p +2 = 8 8p = 6
5. Solve by Elimination ! Mult. By 9 3x +3 = y 3x – y = -3 ADD! -3x – 2y = -6
6. Solve by Elimination ! Mult. By 4 Mult. By 3 Marker Boards: evens 8x-12y=-4 9x+12y=24 17x=20
What happens if solving by substitution or elimination and the variables add out? There is either no solution or infinitely many You do not have to work out this problem in your notes – but after viewing the example, summarize this Q&A in the “side bar” of your notes! If the result had been true the answer to the problem would have been “infinitely many solutions” Example:#7 2p + 3 = z 2p + 4 = z 2p + 3 = 2p + 4 Notice the variables added out. Since the result is false, there is “no solution” to this problem
8. Solve the system by graphing. y • • • • x •
9. Solve the system by graphing. Hint: Standard form so use intercepts to graph! y Marker Boards: odds • • Side bar reiminder? x • •
How can one check to determine if the answer to a system of equations is correct? Summarize this Q&A in the “side bar” of your notes! Sub the ordered pair back in to BOTH original equations and BOTH equations should balance!
Reminder from Algebra 1: How can you solve these on the calculator? Summarize this Q&A in the “side bar” of your notes! • Put both eq. in slope–intercept form • Type into y1 and y2 • 2nd, trace, #5, enter, enter, enter • If error msg, stretch window
NOW: Look at problems 9-12 on HW3.1. Using Algebra 1 skills, write the 2 equations for each of these HW problems on the HW packet. We will go over these equations before you leave class today to be certain you are solving the correct problems! After you have the equations for #9-12, start working problem #1 in your actual spiral.
Your equations and variable choices might be different 10. 2n + 3m = 158 3n + 5m = 248.5 • F = 6m + 78 • F = 4m + 104 12. I + O = 7722 I = 1.2O 11. x = 14 + 2y x + y = 90 Incumbent earned 100% + 20% of opponents votes Incumbent means an official currently holding office