Unit 6: Geometry and Construction 

Day 1: 

• Objective: Students will solve systems of equations by graphing and demonstrating an ability to make wise business decisions.
• Although some companies may seem cheaper than others, you have to figure out the total price for the job you want done.  For example, some companies may be cheaper for shorter periods of time, and some may be cheaper for longer periods of time.  To start, it is helpful to create an equation for each company and then graphing the equations to solve the system. 

Quiz Time!

1.) Solve the system by graphing(find the solution):

     y= x+1

     y= -5/3x+9

2.) Katey's carpet company charges a fee of $30 and then $2 per square of carpet to install. Morgan's company charges a fee of $45

but only $1 per square of carpet to install.  If a costumer wanted to install

10 squares of carpet, which company would be the cheapest? Write an 

equation for each company and then graph.

3.)Solve the system by graphing(find the solution): 

     y= 2x+7

     y= -2x+1

Answers to the quiz: 

1.) When you graph both of the lines, the point where they

intersect is the solution: 

2.) To write equations, you have to know what the y-intercept is and what the slope is.
The fees are the y-intercepts because you only pay it once(cost at zero squares.) The cost
per carpet square is the slope because that is the constant rate. Once you graph the two lines,
whichever line has the cheapest price at 10 squares is the answer. (see picture below)

3.) When you graph both of the lines, the point where they

intersect is the solution:

For more on how to solve a system of equations while graphing watch this: http://youtu.be/cuNpXve18Pc