How do you write 21 in scientific notation?

Answers

Answer 1

Answer:

Answer:21 = 2.1 × 101

Step-by-step explanation:

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Why is the answer A? Plz explain.
2 2/ 3 x 4/5 Multiply mixed numbers
Inequalities x minus -3>-15
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Gavin and Ethan are training for a race. Last week, Gavin ran 7 kilometers, and Ethan ran twice as far as Gavin. What is the total distance that Gavin and Ethan ran last week? Express your answer in meters.

The circles below are concentricWhat is the measure of the angle formed by the two secants?
What is the value of x?

Answers

Given:

Intercepted arcs of small circle:

78° and x°

Intercepted arcs of large circle:

57° and 121°

To find:

The measure of angle formed by two secants and the value of x.

Solution:

Consider a large circle:

The angle made by two secants intersecting outside a circle is half the difference between the measure of intercepted arcs.

$$\Rightarrow \text{ angle} =(1)/(2)(121^\circ-57^\circ)$

$$\Rightarrow \text{ angle} =(1)/(2)(64^\circ)$

$$\Rightarrow \text{ angle} =32^\circ$

The measure of the angle formed by two secants is 32°.

Two circles are concentric circles.

Therefore 32° is also the angle made by small circle arcs.

$$\Rightarrow 32^\circ=(1)/(2)(x^\circ-78^\circ)$

Multiply by 2 on both sides.

$$\Rightarrow 2* 32^\circ= 2* (1)/(2)(x^\circ-78^\circ)$

$$\Rightarrow 64^\circ= x^\circ-78^\circ$

Add 78° on both sides.

$$\Rightarrow 64^\circ+78^\circ= x^\circ-78^\circ+78^\circ$

$$\Rightarrow 142^\circ= x^\circ$

The value of x is 124.

Which statement about 4x2 + 19x – 5 is true? One of the factors is (x – 4). One of the factors is (4x + 1). One of the factors is (4x – 5). One of the factors is (x + 5).

Answers

Answer:

Only "One of the factors is (x + 5)." is TRUE.

Step-by-step explanation:

What makes $(x-4)$ equal to 0?

$x-4=0\nx=4$

What makes $(4x+1)$ equal to 0?

$4x+1=0\n4x=-1\nx=-(1)/(4)$

What makes $(4x-5)$ equal to 0?

$4x-5=0\n4x=5\nx=(5)/(4)$

What makes $(x+5)$ equal to 0?

$x+5=0\nx=-5$

Note: Putting all those 4 values into the function $4x^(2)+19x-5$ , whichever value makes the function equal to 0, the corresponding expression would be considered a factor of the function $4x^2+19x-5$ .

Putting $x=4$ into $4x^(2)+19x-5$ gives us:

$4(4)^(2)+19(4)-5\n=135$

Putting $x=-(1)/(4)$ into $4x^(2)+19x-5$ gives us:

$4(-(1)/(4))^(2)+19(-(1)/(4))-5\n=-(19)/(2)$

Putting $x=(5)/(4)$ into $4x^(2)+19x-5$ gives us:

$4((5)/(4))^(2)+19((5)/(4))-5\n=25$

Putting $x=-5$ into $4x^(2)+19x-5$ gives us:

$4(-5)^(2)+19(-5)-5\n=0$

As we can see, only putting $x=-5$ in the function gives us a value of 0. So the corresponding expression $(x+5)$ is a factor of the function.

$4 x^(2) + 19x - 5 \n \n 4 x^(2) + 20x - x - 5 \n \n 4x(x + 5)-(x + 5) \n \n (x + 5)(4x - 1)$

The answer is D) one of the factors of (x + 5). Why?

(x - 4) is not one of the factors.
(4x + 1) is not one of the factors.
(4x - 5) is not one of the factors.
(x + 5) IS one of the factors.

How can you use 4s fact to find 7x8? Give the product in your explanation.

Answers

Final answer:

You can use the 4s fact to find the product of 7 and 8 by breaking down 7 x 8 into (4 x 2) x 8, then rearrange to (4 x 8) x 2. Thus, the product of 7 and 8 is 64.

Explanation:

The question relates to using the known multiplication fact of 4 to find the product of 7 and 8. The method involves breaking down 7 x 8 into (4 x 2) x 8, which could be rearranged to (4 x 8) x 2 = 32 x 2 = 64. By using the 4s fact, we first multiplied 4 by 8 to get 32, then multiply the result by 2 to derive the product of 7 and 8.

Learn more about Multiplication here:

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Final answer:

You can find 7x8 using 4s facts by adding the product of 4x8 to the product of 3x8, which is 32 + 24 = 56.

Explanation:

You can use the 4s facts to find the product of 7x8 by doubling twice. Here's how it works:

First, use the 4s fact, which you should know is 4x8=32.
Then, knowing that 7 is 4+3, you can use the product you already found and the 3s fact (3x8=24), to find 7x8. Add the two products together: 32 (for 4x8) + 24 (for 3x8) = 56.

Therefore, the product of 7x8 is 56.

Learn more about Multiplication using 4s facts here:

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Which statement is true about the following system of equations3x-1/2y=1
x+2y=7
A)y=x
B)y<x
C)it cannot be determined
D)y>x

Answers

$\left\{\begin{array}{ccc}(3x-1)/(2y)=1\nx+2y=7\end{array}\right\n\n\left\{\begin{array}{ccc}(3x-1)/(2y)=1\n2y=7-x\end{array}\right\n\nsubstitute:\n\n(3x-1)/(7-x)=1\iff3x-1=7-x\n\n3x+x=7+1\n4x=8\nx=2\n\n2y=7-2\n2y=5\ny=2.5\n\nAnswer:D)\ y > x$

You have to solve the system of equations for 'x' and 'y'. When you do that,
you discover that x=0.846 and y=3.076. So Y > X .

Pete earns $8.50 per hour plus tips. On Tuesday, he received $16 in tips.How many hours did Pete work if he earned a total of $50 on Tuesday?

Help me plz

Answers

Answer:

Pete worked for 4 hours.

Step-by-step explanation:

If you subtract his tips from his overall total (50-16) you get 34. Now you divide what's left of his total by his hourly wage (34/8.5) which gets you 4.

List five rational numbers between -2 and-1
List five rational numbers between-2and-1

Answers

Rational number just means that you can express it as a fraction, where both the numerator and denominator are integers & the denominator isn't 0.

Remember: whole numbers can be fractions. But, for example, the sqrt of 2 is irrational.

So:

-1.5

-1.75

-1.2

-1.9

-1.3

All of these are btwn -2 and -1. And they are all rational.

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Lola needs to sign 96 invitations. Using a stopwatch that measures time to tenths of a second, it takes Lola 5.3 seconds to sign her full name. Going by the accuracy of the stopwatch, using this as the accurate determination,how long will Lola be able to finish signing all the invitations? A. 3.3 minutes B. 3.3125 minutes C. 8.48 minutes D. 8.5 minutes

Danae is choosing between two jobs. One job pays an annual bonus of $1,500 plus $120 per day worked. The second job pays an annual bonus of $2,500 plus $110 per day worked. Which equation can be solved to determine after how many days, d, Danae would make the same amount of money regardless of the job she chooses?120d + 110d = 1,500 + 2,500 120 + 110 = 1,500d + 2,500d 120d + 1,500 = 110d + 2,500 120d + 2,500 = 110d + 1,500

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A 50 ft tall tree is casting a shadow while the sun is at an angle of elevation of 63  . to the nearest foot, how long is the tree's shadow?