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omeli [17]
3 years ago
15

PLEASE HELP ASAP (MORE THEN ONE ANSWER)

Mathematics
1 answer:
r-ruslan [8.4K]3 years ago
6 0
When we say "closed under addition" in the context of rational numbers, we mean to say that when we add up rational numbers then, the sum is also a rational number. 

From the given choices above, the one that should the characteristic of being "closed under addition" is only fourth equation. Both 1/2 and 0.5 are rational numbers. On the other hand, 1 is also a rational number. 
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Find the vertex of the parabola formed by the following quadratic function: y = 3x^2 – 6x + 2
storchak [24]
Vertex form is y=a(x-h)^2+k, so we can rearrange to that form...

y=3x^2-6x+2  subtract 2 from both sides

y-2=3x^2-6x  divide both sides by 3

(y-2)/3=x^2-2x, halve the linear coefficient, square it, add it to both sides...in this case:  (-2/2)^2=1 so

(y-2)/3+1=x^2-2x+1  now the right side is a perfect square

(y-2+3)/3=(x-1)^2

(y+1)/3=(x-1)^2  multiply both sides by 3

y+1=3(x-1)^2  subtract 1 from both sides

y=3(x-1)^2-1  so the vertex is:

(1, -1)

...

Now if you'd like you can commit to memory the vertex point for any parabola so you don't have to do the calculations like what we did above.  The vertex of any quadratic (parabola), ax^2+bx+c is:

x= -b/(2a),   y= (4ac-b^2)/(4a)

Then you will always be able to do a quick calculation of the vertex :)
7 0
4 years ago
A cone has a volume of 5 cubic inches. What is the volume of a cylinder that the cone fits exactly inside of?
DENIUS [597]
The answer is 15 in³.

The volume of the cone is:
V_1= \pi r_1 ^{2}  \frac{h_1}{3} = \frac{ \pi  r_1^{2} h_1}{3}
where:
V₁ - the volume of the cone
r₁ - the radius of the cone
h₁ - the height of the cone

The volume of the cylinder is:
V_2= \pi  r_2h_2^{2}
where:
V₂ - the volume of the cone
r₂ - the radius of the cone
h₂ - the height of the cone

Since <span>the cone fits exactly inside of the cylinder, they have the same radius and the height:
r</span>₁ = r₂
h₁ = h₂

Also:
V₁ = 5

Now, let's write two volume formulas together:
V_1= \frac{ \pi r^{2} h}{3}
<span>V_2= \pi rh^{2}</span>

We can include V₂ into V₁:
V_1= \frac{V_2}{3}

⇒ V_2=3*V_1
V_2=3*5 in^{3}
V_2=15 in^{3}
5 0
3 years ago
Here are two patterns made using identical rhombuses. Without using a protractor, determine the value of a and b.
satela [25.4K]

Answer:

<em>a = </em>60°

<em>b </em>=<em> </em>120°

Step-by-step explanation:

First, you can find measure <em>a </em>by using the first shape. There are six rhombuses, and you can use the innermost <em>a </em>of each one to form a circle. A full circle is 360°, so divide 360 by six. The answer is sixty. So on the next shape, the <em>a</em> measurements add up to 120°. Subtract that from the circle: 360 - 120 = 240. And since there are two measurements for <em>b</em>, you would divide 240 by two. The answer is 120.

To check your work, use the knowledge that circles are 360° (the four interior corners of a rhombus will also add up to 360°. 2(120) + 2(60) = 360. Hope this helps! Feel free to ask any questions!

7 0
3 years ago
Read 2 more answers
5 (10k + 1) + 2 (2 + 8k)
Eddi Din [679]

Answer:

66k+9

Step-by-step explanation:

Simplify: 50k+5+4+16k

Combine like-terms: 66k+9

Hope this helps

6 0
3 years ago
Read 2 more answers
Help answer 16 don’t mind the writing just help answer the problem
beks73 [17]

Answer:

6 weeks.

Step-by-step explanation:

Im gonna explain it anyway.

324 divided by 54 is 6. so it will take 6 weeks.

5 0
3 years ago
Read 2 more answers
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