Lesson 6-4 Day 2 Slope Intercept Form Objectives: Students will be able to: write equations using slope-intercept form. identify slope and y-intercept from an equation.

b represents the y-intercept Important!!! This is one of the big concepts in Algebra 1. You need to thoroughly understand this! Slope – Intercept Form y = mx + b m represents the slope b represents the y-intercept

Writing Equations When asked to write an equation, you need to know two things – slope (m) and y-intercept (b).

We have both!! Plug them into slope-intercept form Writing Equations Write an equation in slope-intercept form of the line that has a slope of 2 and a y- intercept of 6. To write an equation, you need two things: slope (m) = y – intercept (b) = We have both!! Plug them into slope-intercept form y = mx + b 2 6 y = 2x + 6

y = -3x – 4 y = -4x – 3 y = -3x + 4 y = -4x + 3 Write the equation of a line that has a y-intercept of -3 and a slope of -4. y = -3x – 4 y = -4x – 3 y = -3x + 4 y = -4x + 3

Graphing using Slope Intercept (y = mx + b)  Put equation in slope intercept form Plot the y-intercept Use slope to find 2 more points

Graphing using Slope Intercept (y = mx + b) b = -3 (y-intercept) plot (0,-3) y = 1/3 x - 3 m = 1/3 (slope rise/run) positive leans right plot up 1, right 3 plot down 1, left 3 connect the points

Graphing using Slope Intercept Form (y = mx + b) b = 2 (y-intercept) plot (0,2) y = -1/2 x + 2 m = -1/2 (slope rise/run) negative leans left plot up 1, left 2 plot down 1, right 2 connect the points

Find the slope and y-intercept. y = 3x – 7 y = mx + b m = 3, b = -7 To find the slope and y-intercept of an equation, write the equation in slope-intercept form: y = mx + b. Find the slope and y-intercept. y = 3x – 7 y = mx + b m = 3, b = -7

Find the slope and y-intercept. 2) y = x y = mx + b y = x + 0 3) y = 5 y = 0x + 5 m = b = 0 m = 0 b = 5

Find the slope and y-intercept. 4) 5x - 3y = 6 Write it in slope-intercept form. (y = mx + b) 5x – 3y = 6 -3y = -5x + 6 -3 -3 -3 m = b = -2 y = x - 2

Find the slope and y-intercept. 5) 2y + 2 = 4x Write it in slope-intercept form. (y = mx + b) 2y + 2 = 4x 2y = 4x - 2 2 2 2 m = 2 b = -1 y = 2x - 1

Find the slope and y-intercept of y = -2x + 4 m = 2; b = 4 m = 4; b = 2 m = -2; b = 4 m = 4; b = -2

Homework: p. 351 # 28 – 39 all