In the education field there is a large demand for classroom supplies. Most teachers receive a little financial help, but it rarely covers the cost for the whole year. With this in mind, many teachers need to purchase school supplies with their own money. Living on a teacher’s salary many times means watching every dollar. If a teacher needs to spend his or her own money on supplies for their room, their going to shop around for the best deal out there.

A week before the start of school there are two school and office supply stores offering sales. Apple (“A”) Office Supplies is offering a 20% off sale on complete purchases. Banana (“B”) School Supply is offering a sale in which there is a 25% discount for every dollar amount spent above $20.00. Using two different algebraic equations I will evaluate and compare the two cost options. After solving the systems of equations I will depict the situation graphically using separate amounts of total funds spent in range from $20-$300.00.

X= Dollar amount before discount

Y= Dollar amount after discount

Store “A” 20% off total sales 0.8X = Y

The dollar amount before the discount is multiplied by 80% (.80). This is algebraically the use of the substitution method. The dollar amount before the discount is substituted for X, and then multiplied by .80 which in turn will give you the answer to Y. Y is the final sale price.

Store “B” 25% off every dollar (X-20).75 + 20 = YX >20

Amount spent above $20.00.75X – 15 + 20 = Y

.75X + 5 = Y

. The dollar amount before the discount is substituted for X. This is algebraically the use of the substitution method, then X is multiplied by .75 and .75 is multiplied by negative 20 using distribution. The like terms of .75 multiplied by the substituted value for X, negative 15, and 20 are added which in turn will give you the answer to Y. Because the discount does not take effect until the purchase is over...

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