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nydimaria [60]
3 years ago
12

A used book store is selling 3 records and 5 CDs for $60. You can also buy 6 records and 4 CDs for $80. Find the cost of one CD.

Write the linear system that describes this situation.​
Mathematics
1 answer:
krek1111 [17]3 years ago
5 0

9514 1404 393

Answer:

  3r +5c = 60

  6r +4c = 80

Step-by-step explanation:

There are many aspects of "this situation" that could be described by equations. We are guessing that you want equations that will help you determine the costs of a record and a CD, assuming the costs are the same for each instance of the media.

Let r and c represent the costs of a record and a CD, respectively.

  3r +5c = 60 . . . . . . . the value of the first purchase

  6r +4c = 80 . . . . . . . the value of the second purchase

These equations comprise a linear system describing an aspect of the situation.

_____

<em>Comment on the question</em>

The numbers make no sense, as the cost of a CD is $(6 2/3), the cost of a record is $(8 8/9).

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Given that OA = 2x + 9y, OB = 4x + 8y and CD = 4x - 2y, explain the geometrical relationships between the straight lines AB and
Step2247 [10]

Answer:

The geometrical relationships between the straight lines AB and CD is that they have the same slope

Step-by-step explanation:

Given

OA = 2x + 9y

OB = 4x + 8y

CD = 4x - 2y

Required

The relationship between AB, CD

Since AB is a straight line and O is the origin, then:

AB = (c - a)x + (d - b)y

Where:

OA = ax + by ====> OA = 2x + 9y

OB = cx + dy ====> OB = 4x + 8y

This implies that:

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So:

AB = (c - a)x + (d - b)y

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So, we have:

AB = 2x  -y

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For AB

m_1 = \frac{-1}{2}

m_1 = -\frac{1}{2}

For CD

m_2 = \frac{-2}{4}

m_2 = \frac{-1}{2}

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By comparison:

m_1 = m_2 = -\frac{1}{2}

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Step-by-step explanation:

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