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Margarita [4]
3 years ago
13

Kevin's work for deriving the equation of a circle is shown below. x2 + 4x = −(y2 − 20) step 1 x2 + 4x = −y2 + 20 step 2 x2 + 4x

+ 4 = −y2 + 20 − 4 step 3 (x + 2)2 = −y2 + 20 − 4 step 4 (x + 2)2 + y2 = 16 in which step did he make an error in his work
Mathematics
1 answer:
SVEN [57.7K]3 years ago
7 0
We have the following equation:
 x2 + 4x = - (y2 - 20)
 Let's review step by step:
 step 1:
 
x2 + 4x = -y2 + 20
 Answer: OK
 step 2:
 
x2 + 4x + 4 = -y2 + 20 - 4
 Answer: Wrong
 The correct step is:
 x2 + 4x - 4 = -y2 + 20 - 4
 Or equivalently:
 x2 + 4x + 4 = -y2 + 20 + 4
 Answer:
 
he did make an error in his work in step 2
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What is the equation of the following line? be sure to scroll down first to see all answer options
andreyandreev [35.5K]

Answer:

The equation for the following graph:

y = -\frac{1}{5}x

Step-by-step explanation:

- You first need to find the slope by using the <u>slope formula</u>:

m = \frac{y_{2} - y_{1}}{x_{2} - x_{1}}

(where (x_{1},y_{1}) is the first point and (x_{2}, y_{2}) is the second point)

-Use the given points (0,0) and (10, -2) from the graph for the formula:

m = \frac{-2 - 0}{10 - 0}

Then, you solve:

m = \frac{-2 - 0}{10 - 0}

m = -\frac{1}{5}

After you have found the slope, use the slope -\frac{1}{5} and the first point (0,0) for the <u>point-slope formula:</u>

y - y_{1} = m ( x - x_{1})

<u>(</u>where m is the slope and (x_{1}, y_{1}) is the first point)

y - 0 = -\frac{1}{5}  ( x - 0)

Then, you solve:

y - 0 = -\frac{1}{5}  ( x - 0)

y - 0 = -\frac{1}{5}x - 0

y - 0 + 0 = -\frac{1}{5} - 0 + 0

y = -\frac{1}{5}x

So, the equation for the following graph is y = -\frac{1}{5}x .

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3 years ago
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Read 2 more answers
The cardinal number of {208,209,210,211,....,1007} is
levacccp [35]

Answer:

\large \boxed{800}

Step-by-step explanation:

A cardinal number is the number of distinct elements in a finite set.

Your set consists the integers from 208 to 1007.

Each element is 1 more than the preceding element, so it represents an arithmetic sequence with distinct elements.

The formula for  the nth term in an arithmetic sequence is

aₙ = a₁ + (n - 1)d, where

a₁ = the first element of the sequence

n = the common difference between successive terms

In your sequence,

a₁ = 208 and d = 1

To figure out how many elements are in the set, set aₙ to 1007 —  the last member —  and solve for n.

\begin{array}{rcl}a_{n} & = & a_{1} + (n - 1)d\\1007 & = & 208 + (n - 1) \times 1\\1007 & = &208 + n - 1\\1007 & = &207 + n\\n & = & \mathbf{800}\\\end{array}\\\text{The cardinal number is $\large \boxed{\mathbf{800}}$}

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3 years ago
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rjkz [21]

Answer:

UP THE DOWN THAT WHAT I GOT

Step-by-step explanation:

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Answer:

-4(2+i)

Step-by-step explanation:

-8-4i (can factor out a 4)

-4(2+i)

7 0
3 years ago
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