Transcript Algebra 1

Chapter 5
 Graph
the following equation using slopeintercept form:
y  4x  5
 On
the back of your paper evaluate the
following:
8
 7
(3)( 5)
 Objective:
Use slope-intercept form to write
the equation of a line. Model real-life
situations with a linear function.




PE’s:
A1.4.B Write and graph an equation for a line given the
slope and y-intercept, the slope and a point on the line, or
two points on the line and translate between forms of
linear equations.
A1.4.C Identify and interpret the slope and intercepts of a
linear function, including equations for parallel and
perpendicular lines.
A1.4.E Describe how changes in the parameters of linear
functions and functions containing an absolute value of a
linear expression affect their graphs and the relationships
the represent.
Pg.
276 #1-11
 Write
an equation that represents the
following situation.

Bobby’s Car Rentals rents cars for a base fee of
$150 and then charges $0.20 per mile after that.
 How
much will it cost to rent a car to travel
to Seattle, which is 300 miles away?
 Objective:
Use slope and any point on a line
to write an equation of the line
 Write
an equation for the line that passes
through the point (6, -3) and has a slope of
-2.
Do problems 1-15odd on homework
 Write
an equation for the line with slope -3
and passing through the point (-2, 8)
 Use
the distributive property to simplify the
following:
2 y (3 y  2)  y
 Write
an equation for the line that is parallel
2
to y  x  2 and passes through the point
3
(-2, 1).
 If
two lines are parallel they have the same
slope
do problems 16-18
VACATION TRIPS Between 1985 and 1995, the
number of vacation trips in the United States
taken by United States residents increased by
about 26 million per year. In 1993, United States
residents went on 740 million vacation trips
within the United States.
a. Write a linear equation that models the
number of vacation trips y (in millions) in terms
of the year t. Let t be the number of years since
1985.
b. Estimate the number of vacation trips in the
year 2005.
Do problems 19-24
 Find
the slope of the line that passes through
the points (3,6) and (-2,-1)
 Graph
a line with the above slope that goes
through the point (2,-1)
 Solve
the following equation for y:
2(3 y  2)  y  7
 Objective:
Write an equation of a line given
two points on the line
 Step
1- find the slope of the two points using
y2  y1
slope 
x2  x1
 Step
2- use the slope and one of the points to
find the y-intercept
 Step
3- write the equation using
y  mx  b
 Worksheet
5.3B finish 1-11 for tomorrow,
whole worksheet due Wednesday
 Find
an equation of the line that goes
through the points (4,5) and (-1,-2).
 Solve
the following equation for a:
3a  2  5a  6
 Perpendicular
lines are lines that cross at a
right angle (90 degrees)
 If
two lines are perpendicular, then their
slopes are the opposite reciprocals of each
other
4
 If the slope of a line is
3
a perpendicular line is 3

4
then the slope of
 Worksheet
5.3B whole thing due tomorrow
 complete
the mini quiz for section 5.3
 Objective:
Find a linear equation that
approximates a set of data points. Determine
whether there is a positive or negative
correlation in a set of real life data.
 Best-fit
line- A line that represents a
collection of data, even if you can’t draw a
line through all of the points
 Sometimes
there is no line of best fit
Best-fit line- A line that represents
a collection of data, even if you
can’t draw a line through all of
the points. Sometimes there is no
line of best fit
 Positive correlation- when the line
of best fit has a positive slope
 Negative correlation- when the
line of best fit has a negative
slope
 No correlation- when there is no
good line of best fit
o
 Step
1: Draw the line of best fit.
 Step
2: pick two points on the line.
 Step
3: use what we learned in 5.3 to make
an equation for the line.

Figure out your neighbor’s age in months, height
in inches, forearm length in inches and math
grade by percent. You may need a ruler.
Choose one partner to go up to the board and
record your findings.
 For example, my stats are:
 68 inches tall
 9 inch forearm length
 284 months old
 97% in freshman algebra

 Pick
one of the following to make a scatter
plot of:
 forearm vs. height
 age vs. grade
 Forearm vs. grade
 Age vs. height
 After
you are done making a scatter plot, see
if you can find a line of best fit.
 Note:
make sure you use tails plus
Think back to the activity that we did on Friday.
 1.) which sets of data have a positive
correlation? Negative? none?


2.) what do you think the correlation would be
between forearm and age? Grade and height?

3.) what are some other collections of data that
might have correlations? Give an example of a
positive correlation, negative correlation and no
correlation.
 Objective:
use point-slope form to write an
equation of a line. Use point slope form to
model a real-life situation.
 The
point-slope form of the equation of the
non-vertical line that passes through a given
point (x1, y1) with a slope of m is
y  y1  m( x  x1 )
 5.5
practice B
 Write
the equation of the line that goes
through the points (-1,-3) and (-2,-5) in
point-slope form.
 Rewrite
the equation in slope-intercept form
and state the y-intercept.
I
walk at a rate of 4 miles per hour. Write a
linear equation to model the distance I am
from my house if after 3 hours of walking I
am 20 miles from home.
 How
far away from home was I when I
started walking?
 Objective:
Write a linear equation in
standard form. Use the standard form of an
equation to model a real life situation.
 The
standard form of a linear equation is:
Ax  By  C
where A, B, and C are real numbers.
 Write
an equation in standard form for the
line that passes through the point (-4,3) and
has a slope of -2.
 List
three different basic forms of a linear
equation.
 Take
a copy of the chapter 4 cumulative
review worksheet and start working on it.
I
am driving to Seattle, which is about 226
miles away. I leave at 6:30am and get to
Ellensburg at 8:30am and Ellensburg is 120
miles from Kennewick.
 Write
an equation to represent this situation
and draw a graph to represent it.
 List
and write out the three different forms
of a linear equation
 You
are buying $48 worth of lawn seed that
consists of two types of seed. One type is a
quick growing rye grass that costs $4 per
pound, and the other type is a higher-quality
seed that costs $6 per pound.
 1.) Write an equation that represents the
different amounts of $4 seed, x, and $6
seed, y, that you can buy.
 2.) rewrite the equation from 1 in slopeintercept form.
 3.) Graph the equation.
 Pg.
311 #1-15odd, 16&17
 5.5
standardized test practice
 Objective:
Determine whether a linear model
is appropriate. Use a linear model to make a
real-life prediction.
 Data
that can be represented by a linear
model should increase or decrease at a
mostly constant rate.
 Linear
interpolation- a method of estimating
the coordinates of a point that lies between
two given data points.
 Linear
extrapolation- a method of estimating
the coordinates of a point to the right or left
of all of the given data points.
 5.7B
#1-10
 Grab
a copy of chapter 5 test.
 On the back of it write:
1.) the three forms of a linear equation
2.) the two formulas for slope.
 Review
worksheet