Lesson 4.3

Slope Intercept FormLesson 4.3Graphing Lines using SlopeWe can graph a line using only 2 pieces of information:The slope of the line (m)The y-intercept (b)Slope-Intercept FormBecause of this, a common way to write equations is using slope-intercept form. y=mx+bwhere m is the slopeand b is the y-interceptBegin with the BasicsBegin with the BasicsEx2) Identify the slope and y-intercept of the following equations.

a) y = 2x + 4 b)

Begin with the BasicsEx3) Write the equation for the following lines in slope-intercept form. a) b)

Re-writing equations Ex4) Re-write the following equation in slope-intercept form. Then identify the slope and y-intercepta) 2x y = -3 b) 3x + 5y = 15Real World ApplicationEx5) An online store charges $3 per order plus $1.00 per book for shipping. Write a linear equation in slope-intercept to model the situation. Identify the slope and y-intercept. What do they mean in the context of this problem?Real World ApplicationEx6) You want to rent a rowboat for a fishing trip. There is an initial fee of $25, plus a $50 daily fee. Write a linear equation for this situation where y represents the cost of renting a rowboat and x represents the number of days rented.Graphing using Slope-Intercept FormSlope-Intercept form allows us to easily graph lines. Here are the three steps:Use the y-intercept to mark the first pointStarting at the y-intercept, use the slope to get a second pointConnect the points with a straight line (with arrows!)

Graphing using Slope-Intercept FormEx7) Graph the following equations. a) y = 2x 4 Graphing using Slope-Intercept FormGraphing using slope-intercept formEx8) Put the following into slope-intercept form, then graph the equation.a) x + y = 3 Graphing using slope-intercept formEx8) Put the following into slope-intercept form, then graph the equation.b) 5x 2y = 1