Math 60 chapter 3 1pm.notebook
October 02, 2013
3.2 Linear Equations in 2-variables
Standard Form of a Linear Equation of 2-varibles:
Ax + By = C, where A, B, & C are constants.
Consider x - 3y = 1.
Ex: Which pairs (x,y) are solutions of the above equation?
1) (4,1)
2) (1,4)
3) (-2,-1)
May 18-7:10 PM
1
Math 60 chapter 3 1pm.notebook
October 02, 2013
3.2 Linear Equations in 2-variables
Standard Form of a Linear Equation of 2-varibles:
Ax + By = C, where A, B, & C are constants.
Q: How many solutions does the equation x - 3y =1 have?
May 18-7:10 PM
2
Math 60 chapter 3 1pm.notebook
October 02, 2013
3.2 Linear Equations in 2-variables
Standard Form of a Linear Equation of 2-varibles:
Ax + By = C, where A, B, & C are constants.
Q: How many solutions does the equation x - 3y =1 have?
Ex: Find three more solutions to x - 3y = 1.
May 18-7:10 PM
3
Math 60 chapter 3 1pm.notebook
October 02, 2013
Ex: List all the
solutions we found
and use them to
graph x - 3y = 1.
x
y
y
x
May 18-7:50 PM
4
Math 60 chapter 3 1pm.notebook
October 02, 2013
Ex: y = 2x - 3
Find 3 points &
use them to graph
the equation.
x
y
y
x
May 18-7:54 PM
5
Math 60 chapter 3 1pm.notebook
October 02, 2013
Ex: y = 2x
Find 3 points &
use them to graph
the equation.
x
y
y
x
May 18-7:54 PM
6
Math 60 chapter 3 1pm.notebook
October 02, 2013
Sometimes it is convenient to solve equation for y in order to help find points to plot.
Ex: First solve the equation
y
for y and then find three
points to help graph the line.
3x + 5y = 20
x
May 18-7:58 PM
7
Math 60 chapter 3 1pm.notebook
October 02, 2013
Sometimes it is convenient to solve equation for y in order to help find points to plot.
Ex: First solve the equation
y
for y and then find three
points to help graph the line.
3x + 5y = 20
x
May 18-7:58 PM
8
Math 60 chapter 3 1pm.notebook
October 02, 2013
Q: How many points do we need to graph a line?
Q: Why plot 3 points?
Ex: The cost c, in dollars, of shipping a
FedEx Priority Overnight package weighing 1
lb or more a distance of 1001 to 1400 mi is
given by c = 2.8w + 21.05 where w is the
package’s weight in pounds. Graph the
equation and then use the graph to estimate
the cost of shipping a 10 ½-pound package.
y
x
May 18-8:06 PM
9