A. At the beginning of the month, Evan had $24 in his account at the school bookstore. Use a variable to represent the unknown quantity in each transaction below and write an equation to represent it. Then represent each transaction on a number line. What is the unknown quantity in each case? i. First he bought some notebooks and pens that cost $16.
ii. Then he deposited some more money and his account balance was $28.
iii. Then he bought a book for English class that cost $34.
iv. Then he deposited exactly enough money so that he paid off his debt to the bookstore.
b. Explain why it makes sense to use a negative number to represent Evan's account balance when he owes money.
IM Commentary
Many people like to use debt to help students understand negative numbers. When doing so, it is important to keep in mind that representing debt with negative numbers is a convention, and that it would be possible to talk about debt without ever using negative numbers. For example, if I borrow $30 from my cousin, I owe her +30 dollars. If I give her $40, then she owes me +10 dollars. The reason it is so convenient to represent debt with negative numbers is that it allows us to use arithmetic and algebra to keep track of who owes what to whom. Despite the fact that it is convenient to do
1

this story was prepared by jim

mccullaugh in los angeles and

al stewart in new york.

new york the colossal success of "top gun" appears to have dramatically altered madison avenue's

perception of corporate sponsorship

of home video projects.

the paramount home video re- lease, featuring a 60- second diet

pepsi spot, was by no means the

first prerecorded video to carry an advertiser's plug, but it was the

first major theatrical release to do so. in the aftermath of the title's

success, paramount is widely ex- pected to ink a similar deal for

"crocodile dundee" or "star trek

iv" or both.

corporate america's new attraccds push british

recording sales

to 19% gain

london fueled by the compact

disk boom, the value of u.k. manu- facturer shipments of recordings

rose 19% in the 12 -month period ended march 1987, according to the

british phonographic industry.

total value of u.k. shipments for

the period was $755 million for all

configurations. (all value figures

are based on an exchange rate of

$1.68 to the pound sterling.)

cd sales totaled 10.7 million units

worth $121.3 million- compared

with 3.7 million units worth $39.5

million in the prior 12 months -and

accounted for two -thirds of the

overall gain in trade value. at present growth rates, says the bpi, cd

sales for calendar 1987 will reach 20

(continued on page 79)

step-by-step explanation:

y = 3x+4

step-by-step explanation:

to find the slope

slope = (y2-y1)/ (x2-x1)

    = (-8-4)/ (-4-0)

    = -12/-4

  = 3

using the slope intercept form of a line

y= mx+b

we know the slope is 3

we know the y intercept is 4 ( the point where it crosses the y axis or x=0)

y = 3x+4

5: 20

step-by-step explanation: