Building Equations Given Slope and a Point

A-REI.3; F-LE.2; F-CED.2

Table of Contents

38: Guided Practice

39: How Do I Write Equations From Two Points?

EQ: How Do I Write Equations From Two Points? 04/18/23

Point Also known as an ordered pair

Written (x, y)

Slope RiseRun

Change in yChange in x

Rate of change

Represented by “m”

Slope Formula

Point – Slope Form

y – y1 = m(x – x1)

Slope – Intercept Form

y = mx + b

Example 1:Find the equation of the line that passes through (3, 1) and (-4, 15)

y = mx + b

1 = -2(3) + b

1 = -6 + b+6 +6________________ 7 = b

y = -2x + 7

Guided Practice 1Find the equation of the line that passes through (2, -5) and (8, 13)

y = 3x - 11

Follow Up: What is f(-2) for this function?

f(-2) = -17

Guided Practice 2Find the equation of the line that passes through (4, -1) and (-2, 29)

y = -5x + 19

Follow Up: For what x is f(x) = 9?x = 2

Guided Practice 3Find the equation of the line that passes through (80, 198) and (150, 408)

y = 3x – 42

Follow Up: When is the break even point?

When x = 14

QuestionsWhich way do you find easier to solve the problem: Slope intercept form or point slope form? Why?

What do we know about the points we find the slope with in comparison to the line?

Why is knowing the break even point important?

Exit PassIn order to leave today you must:

•Complete and turn in page 33 of your workbook

•Work on your homework