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Gre4nikov [31]
3 years ago
9

The cost of 3 notebooks and 4 pencils is $8.50. Determine the cost of one notebook and one pencil

Mathematics
1 answer:
Assoli18 [71]3 years ago
6 0
Call the notebooks x, and the pencils y. 
<span>3x + 4y = $8.50 and 5x + 8y = $14.50 </span>
<span>Then just solve as simultaneous equations: </span>
<span>3x + 4y = $8.50 </span>
<span>5x + 8y = $14.50 </span>

<span>5(3x + 4y = 8.5) </span>
<span>3(5x + 8y = 14.5) </span>

<span>15x + 20y = 42.5 </span>
<span>15x + 24y = 43.5 </span>

<span>Think: DASS (Different Add, Similar Subtract). 15x appears in both equations so subtract one equation from the other. Eassier to subtract (15x + 20y = 42.5) from (15x + 24y = 43.5) </span>

<span>(15x + 24y = 43.5) - (15x + 20y = 42.5) = (4y = 1) which means y = 0.25. </span>

<span>Then substitue into equation : </span>
<span>15x + 20y = 42.5 </span>
<span>15x + 5 + 42.5 </span>
<span>15x = 42.5 - 5 = 37.5 </span>
<span>15x = 37.5 </span>
<span>x = 2.5 </span>

<span>15x + 24y = 43.5 </span>
<span>15(2.5) + 24(0.25) </span>
<span>37.5 + 6 = 43.5 </span>

<span>So x (notebooks) are 2.5 ($2.50) each and y (pencils) are 0.25 ($0.25) each.</span>
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This answer is the closest to 12 but it doesn't go over 12, so this is less than or equal to 12

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Kindly check explanation

Step-by-step explanation:

When performing addition and subtraction of decimals, it is important to arrange the numbers being added or subtracted such that the decimal points are in line. This is particularly important so that the place value of the numbers are in accord.

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For instance :

6.32 - 0.5

Here, when the decimal point of each number is in line, the tenth placed value of the first number (3) matches the tenth placed number of the second number (5) and all others also fall in place automatically.

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4 0
3 years ago
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Squaring both the sides, we get a quadratic and solving it, we find that the possible values of x are -7 and -4.

Step-by-step explanation:

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[√(x + 8)]² = (x + 6)²

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The possible values of x are -7 and -4.

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brainly.com/question/10572241

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2 years ago
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Answer:

          \large\boxed{\large\boxed{42 unit^2}}

Explanation:

The figure is not a regular hexagon. It is an irregular hexagon.

Please, find attached the picture with the original question and the figure.

You can split the figure into two triangles and one rectangle.

The rectangle has dimensions: 7units × 4units, thus its area is 28 units².

Both the upper triangle and lower triangle have base 7 units and height 2 units.

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