4-2 Writing Equations in Slope-Intercept Form

Hey!! --Youʼre going to use the slope-intercept formula of a line for this whole lesson --

Write it here:

Ex. 1A (-2, 5) slope 3" " " " Ex. 1B (4, -7) slope -1

Ex. 2A (-1, 12) (4, -8)" " " Ex. 2B (5, -8) (-7, 0)

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Write an equation given the slope and a point:

* Write the formula * Plug in the x,y pair and slope* Solve for b* Rewrite the equation with the slope and y-intercept

values substituted (the x and y will still be variables)

Write an equation given two points:

* Find the slope* Use the slope and one of the points (doesnʼt matter

which), and follow the steps above

Ex. 3 CYP In addition to his weekly salary, Ethan is paid $16 per delivery. Last week, he made 5 deliveries, and his total pay was $25. Write a linear equation to find Ethanʼs total weekly pay T if he makes d deliveries.

(linear extrapolation - taking existing data, using the patterns there to write an equation, and using the equation to predict future data. This is often used to analyze situations and make decisions in order to affect future statistics. This is wisdom to a degree...but see BI:)

Ex. 4 CYP How much money will Ethan earn in a week if he makes 8 deliveries.

#9 (see book pg. 227)

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Writing equations from a real-world situation: (You wonʼt be finding each of these every time...just whichever pieces apply to the particular problem, and then using them to find whatʼs missing.)

* Find a y-intercept (This will be a flat fee or starting value of some kind.)* Find a slope (This is the rate of change.)* Find an ordered pair, or two (This will be a particular set of data that go

together.)

Biblical IntegrationBecause God is reliable, we can recognize patterns in His creation and depend on them to continue. However, our understanding of His methods should never replace His voice to us as our means of guidance in decision-making. Even Jesus didn't use His own mind to make decisions...He said that He did nothing of His own accord and that He only said what He heard His Father say and He only did what He saw His Father do. He also told us that He would send us the Holy Spirit and that He would teach us all things and show us what is to come. So basically, the One who knows the future is with you and will guide your every step if you choose to incline your ear to His voice, acknowledging Him in every situation and not operating out of your own understanding...no matter how full it may be.

Problems for Practice: 15, 19, 23, 39, 43, 45 Complete on notebook paper or the back of these printed notes, in notes section of binder. Check with the back of the book. Place a colored check by correct answers. Correct incorrect answers to the right. Use Hotmath if you need help. USE YOUR NOTES AS YOU WORK THESE!!!

Also complete/check the following Spiral/Skills Review: 71, 73

*Don’t forget that extra examples and even a personal tutor explaining examples can be found on your textbook website. Links found on syllabus.

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