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3 years ago

Which of the following sets is NOT closed under addition.

Mathematics

1 answer:

Veronika [31]3 years ago

7 0

Answer:

Step-by-step explanation:

The odd numbers.

Suppose you have 31 and 27 when you add these two together, you get 58 which is not an odd number.

If you need a more mathematical proof, you could do it this way.

2x+1

2x is even. Anything multiplied by 2 is even. When you add 1 you get an odd number

So continue on

2y + 1 is the other number.

2x + 1 + 2y + 1 = 2(x + y) + 2

2 (x + y ) is even. When you add 2 to it, nothing changes. The result is still even.

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svetlana [45]

The first one is A and the second one is C

7 0

3 years ago

Find angle B. What is angle B.

julsineya [31]

Answer:

B=45 Degrees

Step-by-step explanation:

You can use law of sines to answer. Law of Sines states that $\frac{sin(a)}{A} =\frac{sin(b)}{B}$ . That means that $\frac{sin(60)}{4\sqrt{6} }=\frac{sin(b)}{8}$ . Multiplying 8 to both sides gives us $\frac{8sin(60)}{4\sqrt{6} }=sin(b)$ . By using inverse of sin, we get $b = sin^{-1} (\frac{8sin(60)}{4\sqrt{6} } )$ . Plugging that into a calculator gives us b=45 degrees.

7 0

3 years ago

6x + 5y = 4 - 6x + y = 20

Masja [62]

Answer:

x = -8/3

y = 4

Step-by-step explanation:

I assume you want to solve for x and y.

The best way to do this with the two formulas given is elimination. This means add the two equations together.

6x + 5y = 4

-6x + y = 20

The 6 x and -6x will cancel each other. By adding the like terms of the two together you will come out with

6y = 24

Now solve for y by dividing both sides by the 6.

y = 24/6 = 4

Now that we have y, you can plug it into one of the equations and solve for x.

Let's use -6x + y =20.

So plug in the 4 for y to get -6x + 4 = 20

Subtract the 4 from both sides then solve for y by dividing both sides by the -6.

-6x = 16

x = -16/6

You can reduce that down so that x = -8/3.

5 0

3 years ago

Read 2 more answers

6.Calcular: 2^3 ; (-2)^3; ; -2^3 *

olga2289 [7]

Answer:

90-8y66697u

Step-by-step explanation

5 0

2 years ago

A jet climbs at a steady rate at an angle of inclination of 0.5 degree during game off what will its he height be after a 2.2 km

Aneli [31]

A right triangle will be formed with 2.2 km as the hypotenuse, 0.5 degrees as the angle, and an unknown height (see attachment).

Recall the trigonmetric ratios sine, cosine, and tangent that can be used for right triangles.
Sinθ = opposite side/hypotenuse
Cosθ = adjacent side/hypotenuse
tanθ = opposite side / adjacent side
θ (theta) refers to the angle (not the right angle). In this case, θ is the given angle of 0.5°.

In this problem, you will use sine because there is a side opposite to the angle (the unknown side h) and the hypotenuse, and sine relates those two sides.

Let the variable h represent the unknown opposite side, the height.
sin(0.5°) = h / (2.2km)
h = (2.2km)sin(0.5°)
h = 0.019 km

Hope I helped! If you have questions on any of the steps, please comment below.

3 0

3 years ago