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vitfil [10]
4 years ago
8

A store is having a sale on DVDs and CDs. DVDs cost $4 and CDs cost $7. On one day, the store made $204 from DVD and CD sales, a

nd sold a total of 39 items. Write a system of equations, then solve to find how many DVDs and CDs were sold.
Mathematics
1 answer:
Gre4nikov [31]4 years ago
4 0
We are given here the individual costs of DVD and CD as well as the total sales and the number of items sold on one day. To solve the number of DVDs and CDs sold each, we devise two independent linear equations:

(1) x + y = 39
(2) 4x + 7y = 204

x- number of DVDs; y - number of CDs

solving, x= 23 DVDs
y = 16 CDs

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A triangle has a perimeter of 77 cm. One side of the triangle is double the base. The other side is quadruple the base. What are
Step2247 [10]

The three sides of the triangles are 11 cm, 22cm, and 44cm.

<h3>What is the perimeter of a triangle?</h3>

The perimeter of the triangle can be calculated by the sum of all the three sides of the triangle.

A triangle has a perimeter of 77 cm.

Let the side of the triangle be x, y, and the base z.

One side of the triangle is double the base.

x = 2z

The other side is quadruple the base.

y = 4z

The perimeter

X + y + z = 77

or

2z + 4z + z = 77

7z = 77

z = 11

So, the length of base z is 11 cm.

The other sides as

x = 22

y = 44

Therefore,The three sides of the triangles are 11 cm, 22cm, and 44cm.

Learn more about triangle here;

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7 0
2 years ago
Could someone please explain this problem to me?
disa [49]

Answer:

8/3

Step-by-step explanation:

Because all 4 angles are congruent, the sides are proportional.

the scale factor is 5/30 = 1/6.

meaning x = 16(1/6)=8/3.

7 0
2 years ago
Find the equation of the line that passes through the points (–2, 4) and (1, 2).
Stolb23 [73]

Answer:

The answer to your question is c)    y = (-2/3)x + 8/3    

Step-by-step explanation:

Data

A (-2, 4)

B (1, 2)

Process

1.- Calculate the slope of the line

-Formula

  m = (y2 - y1)/(x2 - x1)

  x1 = -2    y1 = 4    x2 = 1   y2 = 2

-Substitution

  m = (2 - 4) / (1 + 2)

-Simplification

  m = -2/3

2.- Find the equation of the line

Formula

    y - y1 = m(x - x1)

-Substitution

   y - 4 = -2/3 (x + 2)

-Simplify

   y - 4 = (-2/3)x - 4/3

   y = (-2/3)x - 4/3 + 4

   y = (-2/3)x - 4/3 + 12/3

-Result

   y = (-2/3)x + 8/3    

3 0
4 years ago
I need a step by step explanation on how you solved the equation.
Ghella [55]

Answer: x=3 and y=−2

Step-by-step explanation:

x=−2y−1;4x−4y=20

Step: Solve x=−2y−1 for x:

Step: Substitute−2y−1 for x in 4x−4y=20:

4x−4y=20

4(−2y−1)−4y=20

−12y−4=20(Simplify both sides of the equation)

−12y−4+4=20+4(Add 4 to both sides)

−12y=24

−12y

−12

=

24

−12

(Divide both sides by -12)

y=−2

Step: Substitute−2 for y x=−2y−1:

x=−2y−1

x=(−2)(−2)−1

x=3(Simplify both sides of the equation)

7 0
3 years ago
Scientific Notation.
iren [92.7K]

400Million meteres tall

scientific notation: 4×10^8

8 0
3 years ago
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