Grade 8 Week 3 Lesson 1: Linear Graphs & Equations PDF

Week 3 15-19 September 2024 lesson 1: x-intercept and y- intercept of a linear graph and equation of a straight line  Objectives. Identify the x and y intercepts on a linear graph. Explain the application of intercepts in real life. Starter Think pair share (10 minute) What do...

Week 3 15-19 September 2024 lesson 1: x-intercept and y- intercept of a linear graph and equation of a straight line  Objectives. Identify the x and y intercepts on a linear graph. Explain the application of intercepts in real life. Starter Think pair share (10 minute) What do you think the word intercept means How does it apply to gragh of a linear equation? Pair and share with a partner your thoughts Share your thoughts with the class  what are x and y intercepts? x-intercept: the point where the line crosses the x-axis (y=0). y-intercept: the point where the line crosses the y-axis (x=0). graph example: y=2x+4 X intercept = -2 Y intercept = 4 Identifying X and Y Intercepts Equation: y=4x+2 Y-Intercept: When x=0, y=2 X-Intercept: When y=0, solve for x What do these intercepts mean in real life? Solve for X and Y Intercepts: y=−3x+6 y = 4x + 12 Equation of a straight line group diacussion Scenario: Buying Concert Tickets Seller A: $50 entry fee + $10 per hour Seller B: $30 entry fee + $20 per hour Question: How would you represent these options mathematically? Option A: P=(10xh) + 50 =10h + 50 Option B: P = (20xh) + 30 = 20h +30 P is the total price h is the number of hours  General Form: y=mx+c m = slope (rate of change) c = y-intercept (starting value/Fixed cost) Example: y=2x+5 Slope = 2, y-intercept = 5 Y = -3x - 4 Slope =-3, y-intercept = -4 Question: What do the slope and intercept represent? Understanding Slope and Y- Intercept Equation 1: y=3x+4 Slope (m): 3 (Rate of change per x unit) Y-Intercept (c): 4 (Initial value) Equation 2: y=−x+7 Slope (m): -1 Y-Intercept (c): 7  Practice exercise Identify the slope and y-intercepts for each of the equations 1.Y= 3x + 5 2.Y = -2x + 7 3.Y= -4x - 5 Plotting Straight Lines Activity: Draw the line graph whoseequation is y=2x+2 identify the y intercept Determine the x intercept Plot the two points intercept draw a straight line through the points Plenary Is there In this ,lesson we have learnt How to identify x and y intercepts from a drawn graph How to find x and y intercepts from an equation of a straight line The general form of equation of a straight line and how it can be modelled from real life scenarios How to identify slope and y intercept from y=mc +c Which section did you find most exciting and why? EXIT TICKET Write down in one sentence the importance of the y-intercept on a straight-line graph. Thank you for participating