Jeudi 23 Septembre Warm up A tennis club membership costs $5 a year. In addition to this flat fee, you must pay $2 every time you reserve a court. Which function rule describes the cost (y) for the number of times you reserve a court(x) A. y = 7 B. y = 5x + 2 C. y = 7x D. y = 2x + 5
Slope intercept form of linear functions · We have learned that every linear function can be expressed by a function rule that looks like this : y = ___ x + ___
· In algebra, we call this form of function rule a slope intercept form. · You'll find it usually expressed as y = mx + b · y and x are variables. They vary! ·m and b are numbers, constant. They stay the same!
40% of the 8th grade math EOG questions, are about finding the value of m or b using: ·The graph ·The function rule ·Coordinates of 2 points ·a real life situation So let's say it's a... VERY important lesson!
b a.k.a the y-intercept · For the real life situation, b is always the flat fee,the guaranteed salary... Basically the part of the cost (salary) that does not depend on the other variable ·On the graph, you can always read it where the line intersects the y-axis. Therefore it's called the y intercept!
Lundi 27 Septembre Warm up 1) What is the y-intercept of this line? 2) Is the slope of this line positive, negative zero or undefined?
Quick review: What do we know so far on linear functions ?
Objective 1: Finding slope on the graph Watch the following segment of video (what is slope from 2:00 mark) and write down steps to find the slope of a line on the graph.
Finding slope on the graph step by step Step 1: Determine sign of the slope (+,-,...) Step 2: Pick 2 points on the line (corners of unit squares) Step 3: Draw a slope triangle Rise first, run second. Rise : up +, down - Run : right +, left - Step 4: Write the fraction rise/run, simplify, check the sign
Guided practice S tep 1: Step 2: Step 3: Step 4:
Independent practice: (will be evaluated) · Front: The 2 points are already picked for you (step 2), focus on the 3 other steps. ·Back page: You have to pick the 2 points, remember to pick them on corners of unit squares Chek with your partners, ask for help, do not stay passive. 90% of the learning happens here!
Objective 2: Matching a linear equation with a graph Which linear equation describes the blue line? A . y = 3x + 2 B. y = -3x - 2 C. y = 3x - 2 D. y = 4x - 2 Step 1 : Find the y-intercept of the blue line. Eliminate answers based on the "b". St ep 2: Determine sign of slope. Eliminate answers based on the sign of "m" St ep 3: Find slope. You should have only one possible answer