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3 years ago

-12 + ( ) = 9 whats the missing number

Mathematics

2 answers:

PilotLPTM [1.2K]3 years ago

7 0

Answer:

The missing number is 21

Step-by-step explanation:

-12 + x = 9

x = 9 + 12

x = 21

erastovalidia [21]3 years ago

3 0

Answer:

Step-by-step explanation:

let X = ( )

-12 + X = 9

X = 9 + 12

X = 21

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HELP PLEASE I WILL GIVE 50 POINTS AND MARK BRAINLESS TO BEST ANSWER

dedylja [7]

Answer:

The answer is 15

Step-by-step explanation:

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7 0

3 years ago

Read 2 more answers

Consider the following problem: A farmer with 750 ft of fencing wants to enclose a rectangular area and then divide it into four

gregori [183]

Answer and step-by-step explanation:

For any rectangle, the one with the largest area will be the one whose dimensions are as close to a square as possible.

However, the dividers change the process to find this maximum somewhat.

Letting x represent two sides of the rectangle and the 3 parallel dividers, we have 2x+3x = 5x.

Letting y represent the other two sides of the rectangle, we have 2y.

We know that 2y + 5x = 750.

Solving for y, we first subtract 5x from each side:

2y + 5x - 5x = 750 - 5x

2y = -5x + 750

Next we divide both sides by 2:

2y/2 = -5x/2 + 750/2

y = -2.5x + 375

We know that the area of a rectangle is given by

A = lw, where l is the length and w is the width. In this rectangle, one dimension is x and the other is y, making the area

A = xy

Substituting the expression for y we just found above, we have

A = x(-2.5x+375)

A = -2.5x² + 375x

This is a quadratic equation, with values a = -2.5, b = 375 and c = 0.

To find the maximum, we will find the vertex. First we find the axis of symmetry, using the equation

x = -b/2a

x = -375/2(-2.5) = -375/-5 = 75

Substituting this back in place of every x in our area equation, we have

A = -2.5x² + 375x

A = -2.5(75)² + 375(75) = -2.5(5625) + 28125 = -14062.5 + 28125 = 14062.5

6 0

3 years ago

For a given triangle it is known that cos A =-0.5, where 0° <br> Based on the information given above, the value of angle(s) A i

Assoli18 [71]

Answer:

120

Step-by-step explanation:

Here, we want to get the possible value of A

Now, we should understand that the value of an angle in triangle cannot be more than 180

Also, cosine can only be negative in the second and the 3rd quadrant

So,

arc cos (-0.5) = 120 , 300 , 60

But 60 is not correct as it will give a negative value

300 is not correct also as it is more than the angles present in a triangle

Thus, our answer is 120

7 0

2 years ago

Please help me! I've tried so hard and just cant

torisob [31]

So... 4 folks, working for 8hours per day, do it in 15days

hmm alrite...so 4 folks working for 8hrs in 1 day, each one does 8, 4 of them, 4*8 = 32, so, they do 32 workhours every day, now for 15 days, that'd be 32*15, or 480

so, the whole job really takes 480 hours

now hmm let's see, the firm decides to increase the folks, but decrease the hours, so, 5 folks each working 6hours every day

how many workhours total? well 5*6 = 30
each is working 6hrs, 5 of them, so 30 workhours

how long will it take them if they only do 30 workhours everyday?

well the whole job is 480hours

$\bf \cfrac{30hrs}{day}=480hrs\implies \cfrac{30hrs}{480hrs}=day\implies \cfrac{1}{16}=day
\\\\\\
\textit{so, if they do }\frac{1}{16}\textit{ daily, to complete, they'd need }\frac{16}{16}\\
\\\\\
\textit{for the whole, thus }16 days$

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2 years ago

The height of a cylinder is 5 centimeters. The diameter of the base of the cylinder is 16 centimeters. Find the lateral surface

soldier1979 [14.2K]

Answer:

Lateral surface area of the cylinder = $251.2 cm^2$