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muminat
2 years ago
7

Mary read 2/5 of a book in 15 minutes. How much of the book can she read per hour? book per hour.​

Mathematics
2 answers:
Yuliya22 [10]2 years ago
8 0

Answer:½((n/2) – ½) – ½ = 10

½(n/2) – ¼ - ½ = 10 (using the distributive property)

¼n – ¼ - ½ = 10 (multiplying to eliminate the parentheses)

¼n – ¾ = 10 (combining like terms)

¼n = 10¾ (adding ¾ to both sides of the equation)

n = 43 (dividing both sides of the equation by ¼)

Step-by-step explanation:

Let’s start by writing Josie’s first step as an expression. Dividing n by 2, then subtracting ½ from

the result would be (n/2) – ½. If we build on this expression with the information in Josie’s

second step, we get ½((n/2) – ½) – ½. Knowing the final result is 10, we can set up the equation

below, and solve for n as follows: hope this helps

Vika [28.1K]2 years ago
3 0

Answer:

Mary can read 8 pages in an hour

Step-by-step explanation:

60/15 = 4

2/5 x 4

2/5 x 20/5

40/5 = 8

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If $-2 < x \le 3,$ then find all possible values of $5x + 1.$ Give your answer in interval notation.
kotegsom [21]

Answer: (-9, 16]

This is the interval from -9 to 16. Exclude -9 but include 16.

=====================================================

Work Shown:

The idea is to multiply all sides by 5, then add 1 to all sides

-2 < x \le 3

5(-2) < 5x \le 5(3)

-10 < 5x \le 15

-10+1 < 5x+1 \le 15+1

-9 < 5x+1 \le 16

This converts to the interval notation  (-9, 16]

note: a curved parenthesis means "do not include this value in the solution set"; while a square bracket has us include the value. So we exclude -9 and include 16.

3 0
3 years ago
Find integrate (1/(xsqrt(1+(lnx)^2)),1,e,x) ...?
prohojiy [21]
Note that x² + 2x + 3 = x² + x + 3 + x. So your integrand can be written as 

<span>(x² + x + 3 + x)/(x² + x + 3) = 1 + x/(x² + x + 3). </span>

<span>Next, complete the square. </span>

<span>x² + x + 3 = x² + x + 1/4 + 11/4 = (x + 1/2)² + (√(11)/2)² </span>

<span>Also, for the x in the numerator </span>

<span>x = x + 1/2 - 1/2. </span>

<span>So </span>

<span>(x² + 2x + 3)/(x² + x + 3) = 1 + (x + 1/2)/[(x + 1/2)² + (√(11)/2)²] - 1/2/[(x + 1/2)² + (√(11)/2)²]. </span>

<span>Integrate term by term to get </span>

<span>∫ (x² + 2x + 3)/(x² + x + 3) dx = x + (1/2) ln(x² + x + 3) - (1/√(11)) arctan(2(x + 1/2)/√(11)) + C </span>

<span>b) Use the fact that ln(x) = 2 ln√(x). Then put u = √(x), du = 1/[2√(x)] dx. </span>

<span>∫ ln(x)/√(x) dx = 4 ∫ ln u du = 4 u ln(u) - u + C = 4√(x) ln√(x) - √(x) + C </span>

<span>= 2 √(x) ln(x) - √(x) + C. </span>

<span>c) There are different approaches to this. One is to multiply and divide by e^x, then use u = e^x. </span>

<span>∫ 1/(e^(-x) + e^x) dx = ∫ e^x/(1 + e^(2x)) dx = ∫ du/(1 + u²) = arctan(u) + C </span>

<span>= arctan(e^x) + C.</span>
4 0
4 years ago
2
rusak2 [61]

Answer:

(1.13, 7.74) and (-4.13, 18.26)

Step-by-step explanation:

This can be solved in two ways:  mathematically and graphically.

<u>Graphing</u>

Plot both lines and find where they intersect.  See the attachment.

The intersection points are (1.13, 7.74) and (-4.13, 18.26)

<u>Mathematical</u>

y + 2x = 10

y = 10 - 2x

y = 3x² + 7x - 4

10 - 2x = 3x² + 7x - 4

3x² + 9x - 14 = 0

Solve this using the quadratic equation:

x = 1.13 and -4.13

Use these two values of x to find y:

y = 10 - 2x

y = 10 - 2(1.13)

y = 7.74

y = 10 -2x

y = 10 -2(-4.13)

y =  18.26

The two points are:

(1.13, 7.74) and (-4.13, 18.26)

7 0
2 years ago
Need help with this question!!
alexira [117]

Answer:

is number 2

Step-by-step explanation:

3 0
3 years ago
How do I find x in this triangle?
Scilla [17]
Since the total degree of a triangle is 180, subtract 44 from 180 = 136. Divide it by two, and you get 68. I believe this is correct but don't take my word for it. Good luck!
7 0
4 years ago
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