In Class/Homework 2 – 06 – 07

Adapted from materials by Alan O'Bryan

The two equations that we used in class came from this scenario:

Two dogs were playing in a yard. Julie's dog Sparky was engaged in a leisurely dig. He was digging at a constant rate of .5 lbs of dirt per minute. When Sparky had 3 lbs dug, the neighbor dog, Rufus noticed the fun Sparky was having and decided to dig too! Rufus, much bigger than Sparky could dig 3lbs of dirt per minute!

y= 3x

y= .5x +3

1) Write the question that would be answered by the "solution" we found graphically.

Graph the following systems of equations. Estimate the solution to each system.

2) y = -2x + 4 3) y = 5x - 1

y = .5x + 1 y = 1.5x + 5

3) You and several of your friends want to go play laser tag at Stratum this Friday. Stratum offers a group rate of $12 per group plus $3 per person. The normal admission is $6 per person.

a) Write a linear function that relates the cost for a group and the number of people who go.

b) Write a linear function that relates the cost for normal admission and the number of people who go

c) Graph the two functions you just wrote.

d) Which way is cheaper if your group has 3 people in it?

e) Which way is cheaper if your group has 7 people in it?

f) How many people need to be in your group for the two to cost the same?

4) Write a word problem that would result in the following system of equations.

y = .5x + 20

y = .10x

b) Write the question based on your scenario that would require the "solution" to your system