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3 years ago

ASAP BRAINLIEST

Mathematics

1 answer:

makvit [3.9K]3 years ago

6 0

Answer:

See answers below with explanations

Step-by-step explanation:

Problem 1:

One number is 10 less than twice another.

This translates to n=2m-10

Their difference is 31

This translates to n-m=31

n-m=31

(2m-10)-m=31

m-10=31

m=41

n-41=31

n=72

Therefore the larger number is (B) 72

Problem 2:

Use elimination:

2x + y = 7

- 2x -3y = -1

4y = 8

y = 2

2x+2=7

2x=5

x=2.5

Therefore the solution is (A) {(2.5,2)}

Problem 3:

Use elimination:

x - y = 1

- x + y = -1

-2y = 2

Check if each answer eliminates to -2y=2:

2x - 3y = 6

4x + y = 4

-2x - 4y = 2 NO

4x - 3y = 6

4x - y = -4

-2y = 10 NO

4x + 3y = -6

4x - y = 4

4y = -10 NO

Neither answer is correct

Problem 4:

No visible items to match

Problem 5:

2(2x - y = -2)

4x - 2y = -4

x + 5y = 3

4x - 2y = -4

5x + 3y = -1

None of the answer choices are correct

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You add all of them together to equal 180 and solve for x.

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3 years ago

A biologist recorded a count of 348 bacteria present in a culture after 5 minutes and 1088 bacteria present after 20 minutes. To

Nat2105 [25]

Answer:

The initial bacteria population is 238

Step-by-step explanation:

Let us have the increase as an exponential equation

P(t) = I(1 + r)^t

where P(t) is the count at a particular time

r is the percentage increase

I is the initial population

t is the time

So for 5 minutes, we have

348 = I(1 + r)^5

For 20 minutes

1088 = I(1 + r)^20

Divide the second equation by the first

1088/348 = I(1 + r)^20/I(1 + r)^5

3.13 = (1 + r)^15

Take the ln of both sides

ln 3.13 = 15 ln (1 + r)

ln 3.13/15 = ln (1 + r)

0.0761 = ln (1 + r)

1 + r = e^0.0761

1 + r = 1.079

r = 1.079-1

r = 0.079 which is 7.9%

So per minute. we have an increase of 7.9%

So let’s get I by substituting

From;

348 = I(1 + 0.079)^5

348/1.079^5 = I

I = 237.9 which is 238 to the nearest whole number

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3 years ago

Dividing polynomials simplify 10c+6÷2

blsea [12.9K]

Answer: 5c+3

Step-by-step explanation: divide regularly. Just keep the C after the 10. I'm not good at explain math sorry.

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4 years ago

What is the solution to the equation?

mojhsa [17]

D. x=−4
Why?
Let's solve your equation step-by-step.
2(x−7)=10x+18
Simplify both sides of the equation.
2(x−7)=10x+18
Simplify:
2x−14=10x+18
Subtract 10x from both sides.
2x−14−10x=10x+18−10x
−8x−14=18
Add 14 to both sides.
−8x−14+14=18+14
−8x=32
Divide both sides by -8.
−8x−8=32−8
D. x=−4

6 0

4 years ago

Read 2 more answers

Find the nth term of the sequence 7,25,51,85,127

olya-2409 [2.1K]

Let a (n) denote the n-th term of the given sequence.

Check the forward differences, and denote the n-th difference by b (n). That is,

b (n) = a (n + 1) - a (n)

These so-called first differences are

b (1) = a (2) - a (1) = 25 - 7 = 18

b (2) = a (3) - a (2) = 51 - 25 = 26

b (3) = a (4) - a (3) = 85 - 51 = 34

b (4) = a (5) - a (4) = 127 - 85 = 42

Now consider this sequence of differences,

18, 26, 34, 42, …

and notice that the difference between consecutive terms in this sequence b is 8:

26 - 18 = 8

34 - 26 = 8

42 - 34 = 8

and so on. This means b is an arithmetic sequence, and in particular follows the rule

b (n) = 18 + 8 (n - 1) = 8n + 10

for n ≥ 1.

So we have

a (n + 1) - a (n) = 8n + 10

or, replacing n + 1 with n,

a (n) = a (n - 1) + 8 (n - 1) + 10

a (n) = a (n - 1) + 8n + 2

We can solve for a (n) by iteratively substituting:

a (n) = [a (n - 2) + 8 (n - 1) + 2] + 8n + 2

a (n) = a (n - 2) + 8 (n + (n - 1)) + 2×2

a (n) = [a (n - 3) + 8 (n - 2) + 2] + 8 (n + (n - 1)) + 2×2

a (n) = a (n - 3) + 8 (n + (n - 1) + (n - 2)) + 3×2

and so on. The pattern should be clear; we end up with

a (n) = a (1) + 8 (n + (n - 1) + … + 3 + 2) + (n - 1)×2

The middle group is the sum,

$\displaystyle 8\sum_{k=2}^nk=8\sum_{k=1}^nk-8=\frac{8n(n+1)}2-8=4n^2+4n-8$

so that

a (n) = a (1) + (4n ² + 4n - 8) + 2 (n - 1)

a (n) = 4n ² + 6n - 3

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3 years ago