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iogann1982 [59]
3 years ago
10

Some of the steps in the derivation of the quadratic formula are shown.

Mathematics
2 answers:
Leokris [45]3 years ago
8 0

Answer:

(C)The square root of terms separated by addition and subtraction cannot be calculated individually.

Step-by-step explanation:

In Step 7:

\dfrac{\pm\sqrt{b^2-4ac} }{2a} =x+\dfrac{b }{2a}

The expression \pm\sqrt{b^2-4ac} cannot be written as b \pm\sqrt{4ac}. This is as a result of the fact that square roots of terms separated by addition and subtraction cannot be calculated individually.

Take these examples:

\sqrt{9-4} =\sqrt{5} \\\sqrt{9}-\sqrt{4}=3-2=1\\ $Clearly \sqrt{5}\neq 1\\$Similarly\\\sqrt{9+4} =\sqrt{13} \\\sqrt{9}+\sqrt{4}=3+2=5\\ $Clearly \sqrt{13}\neq 5\\

eduard3 years ago
4 0

Answer:

C

Step-by-step explanation:

Took the test on edge.

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allochka39001 [22]
D. Multiplication Property
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4 years ago
Twenty years ago, bruce wayne bought a batmobile for 250250250 million dollars. as the crime in gotham city has been down for a
dem82 [27]

Bruce will receive $160 million for the batmobile.

<h3>What is percentage?</h3>

The term "percentage" comes from the Latin phrase "per centum," meaning means "by the hundred." Percentages is fractions with a denominator of 100.

In other terms, it is the relationship between portion and whole in which the value of the whole is always assumed to be 100.

Calculating a percentage implies determining a portion of a whole in term of 100. A percentage can be calculated in two ways:

  1. The unitary technique is used.
  2. By adjusting the fraction's denominator to 100.
  3. It must be noted that second method of percentage calculation is not employed when the denominator isn't a factor of 100. In such circumstances, we employ the unitary technique.

Now, according to the question;

Given that prices fall about 20% every decade;

Thus,  100% - 20% = 80%

He paid $250 million for a batmobile twenty years ago.

Let Bruce to receive x millions of dollars for the batmobile.

⇒ 80% of x = 80/100 × x = 4/5 x

⇒ x = 250(4/5)(4/5)

⇒ x = 250(16/25)

⇒ x = 160

As a result, Bruce will receive 160 millions of dollars for such batmobile.

To know more about the percentage, here

brainly.com/question/317717

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The correct question is-

Twenty years ago, Bruce Wayne bought a batmobile for 250 million dollars. As the crime in Gotham city

has been down for a while, he plans to sell it.

How much can he get for the batmobile if the price goes down by 20% every decade? million dollars

6 0
2 years ago
In the last year, U.S. car sales of all makes and models have dropped by 16%. Let's say that a car dealer sells 325 cars. If thi
IRINA_888 [86]

Answer:

c. 273 cars

Step-by-step explanation:

First you need to find what 16% of 325 is

325x.16=52

because the number sold dropped by 16% you will subtract 52 from 325

325-52=273

you can also calculate the answer by subtracting 100% by 16%

100%-16%=84%

now you can calculate 84% of 325

325x.84=273

6 0
3 years ago
Tan(x+pi/2)= negative cot x
DIA [1.3K]
I'm only going to alter the left hand side. The right side will stay the same the entire time

I'll use the identity tan(x) = sin(x)/cos(x) and cot(x) = cos(x)/sin(x)
I'll also use sin(x+y) = sin(x)cos(y)+cos(x)sin(y) and cos(x+y) = cos(x)cos(y)-sin(x)sin(y)

So with that in mind, this is how the steps would look:

tan(x+pi/2) = -cot x
sin(x+pi/2)/cos(x+pi/2) = -cot x
(sin(x)cos(pi/2)+cos(x)sin(pi/2))/(cos(x)cos(pi/2)-sin(x)sin(pi/2)) = -cot x
(sin(x)*0+cos(x)*1)/(cos(x)*0-sin(x)*1) = -cot x
(0+cos(x))/(-sin(x)-0) = -cot x
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Identity is confirmed

6 0
3 years ago
For every how many degrees will a pentagon have rotational symmetry?
igor_vitrenko [27]
A. 72 degrees (i hope this helped)
7 0
3 years ago
Read 2 more answers
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