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Neporo4naja [7]
2 years ago
8

Fifteen less than twice a number is 21. What is the missing number? |

Mathematics
1 answer:
Vikentia [17]2 years ago
4 0

Answer:

2y - 15

Step-by-step explanation:

well 15 LESS than TWICE a number. okay so let’s start off by making a variable for the unknown number.... y. the variable is y. so now we have to think, TWICE that number, but we don’t know the number.

Now that we have the variable and we know it has to be doubled, let’s start off making the first half... we can out that into 2y. which is 2 multiplied by the unknown number.

now that we have the first half done, we have to take the 15 less. Less can mean  or subtract in this kind of situation. but for this certain scenario, it will be subtraction. so the equation would be 2y - 15.

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Solve for x.
Ostrovityanka [42]

Answer:

C.  3, -7

Step-by-step explanation:

x^2 +4x-21 =0

Factor

What 2 numbers multiply to -21 and add to 4

7*-3 = -21

7-3 = 4

(x+7) (x-3) =0

Using the zero product property

x+7 =0       x-3=0

x+7-7=0-7     x-3+3=0+3

x = -7            x=3

3 0
3 years ago
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Giving brainly to correct answer
Elena L [17]

Answer:

The answer is the second one

im sorry if this is wrong

Step-by-step explanation:

4 0
2 years ago
Read 2 more answers
Due tomorrow please help :)
coldgirl [10]
Okay, so your first one, number six. You have two shapes there, a cone and a circle. Now you have a full cone and a half of a circle. Let's start with the cone. The formula for the volume of a cone is πr²h/3. You have your height, that is 12, so get your paper out and plug that in. H = 12. Now, your radius is where it gets a bit tricky. Have you ever heard of the Pythagorean theorem? It's a²+b²=c². Look at the cone, but look at it like it's a two-dimensional shape. You see the triangle in the middle, ignore the rest and pretend it's only that triangle. You now have a right triangle, You know your height is 12, and by looking at the triangle adjacent to it, and know it's equal, you know that your hypotenuse (the longest side of your triangle) is 15. So plug that into the Pythagorean theorem. Now you have 12²+b²=15². Use algebra to work that out, and you're left with 9. So your radius is 9. Now plug that into your volume of a cone equation. The volume of the cone is about 1017.88. Now find the circle or sphere. The formula is 4/3πr³. Just plug in your radius and get your answer, which is 3053.63. Now cut that in half, as you've only got half a circle. Now you've got 1526.82. Now add that to the volume of your cone, and you've got your final answer. 2544.7, or about that. I used π on a calc, and not 3.14, so it might be a little different.

Do you think you can do the next one? Just look at your triangle in there. You've already got one side and a hypotenuse, so plug it into the Pythagorean theorem and get your last side. Then look at the little marks on there and you can see if places are the same. If you need help with it don't hesitate to ask. I'm staying up all night anyway. Homeschooled and behind, so I'm not going anywhere.
7 0
2 years ago
Emily owns 10.2 shares of stock in a company. On Friday, the stock dropped by $1.35/share. What was the total change in value of
TiliK225 [7]

Answer:

answer is +$7.56

Step-by-step explanation:

I guess I was help full for u

plz follow me for more updates

5 0
3 years ago
HELP I NEED HELP ASAP
pickupchik [31]

Answer:

D

Step-by-step explanation:

Firstly, the question is phrased very very badly as the four answers provided are coordinate points rather than how far apart the cities are in units.

To calculate the distance between two points, we have to use Pythagoras' Theorem as it's just pretty much a right-angle triangle. Please look at the (terribly drawn) image provided.

Keep in mind that these points are only roughly placed on the map.

But firstly, to use Pythagoras' Theorem (a^2 + b^2 = c^2), we must find the length of the two sides.

To find the length of the horizontal line (which from now on I'll refer to as 'a'), we must subtract the smaller x value from the larger one.

47 - 35 = 12

To find the length of the vertical line (which from now on I'll refer to as 'b'), we must subtract the smaller y value from the larger one.

122 - 78 = 44

I assume that the answer you should pick is D. (12, 44)

However, that doesn't exactly answer the question... it's worded a little weirdly.

To solve the rest of the equation, do the following:

Now that we know that the length of a = 12 and the length of b = 44, we can use Pythagoras' Theorem.

a^2 + b^2 = c^2

12^2 + 44^2 = c^2

144 + 1936 = c^2

2080 = c^2

c = \sqrt{2080}

c = 45.61

The answer is 45.61 units.

3 0
2 years ago
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