January 13, 2016 Warm-Up:Warm-Up: As a DecimalAs a Fraction Change to a Percent.75 Solv e:

Homework Writing Equations Using Slope-Intercept Form Worksheet

Objective SWBAT write equations for situations that are not proportional. Write down the objective in your math journal in your own words.

SLOPE-INTERCEPT FORM OF A LINE y = mx + b

VOCABULARY Slope The ratio of vertical change to horizontal change (or rise to run) of a line. Y-intercept The point where the line crosses the y-axis, when x=0.

y = mx + b

The ratio of vertical change to horizontal change (or rise to run) of a line. The “m” in y=mx+b

 Line goes from the bottom left to the top right of a graph.  Both x and y numbers in a table either increase or decrease  The “m” in y=mx+b is positive

 Line goes from the top left to the bottom right of a graph.  Either x or y numbers in a table decrease, while the other increases  The “m” in y=mx+b is negative

 Line is horizontal  x numbers in a table increase or decrease, while the y numbers remain the same  The “m” in y=mx+b is zero, or there is no “mx” term in the equation

 Line is vertical  x numbers in a table remain the same, while the y numbers increase or decrease  The “m” in y=mx+b is divided by zero

1. Count the rise 2. Count the run. 3. Write it as a ratio (fraction): Rise Run Slope =

1. Count the rise (change in y values) 2. Count the run (change in x values) 3. Write it as a ratio (fraction): Slope =

m = the coefficient of x b = the y value of the y-intercept All of the linear equations we’ve studied so far can be written in the form y = mx + b:

Emile d = 2.5t m = b = Henri d = 45 + t m = b =