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3 years ago

12

Have you ever thought about the number of times your heart beats in a life time? Consider the average life span of 75 years and

the average heart beat of 1.2 heartbeats per second. Estimate, using scientific notation, the number of times your heart will beat in your lifetime.

1 answer:

andreev551 [17]3 years ago

7 0

Roughly 2,365,200,000. If you have muiltiple choices round up to the nearest

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HELPPPPP<br> What is the area of the actual living room?

professor190 [17]

Answer:

The answer is 51,200 in².

Step-by-step explanation:

(4x40)x(8x40)=51,200

7 0

3 years ago

Factor 81z^4 - 16<br> Please answer asap

Oksanka [162]

81x%5E4-16 Start with the given expression.

%289x%5E2%29%5E2-16 Rewrite 81x%5E4 as %289x%5E2%29%5E2.

%289x%5E2%29%5E2-%284%29%5E2 Rewrite 16 as %284%29%5E2.

Notice how we have a difference of squares A%5E2-B%5E2 where in this case A=9x%5E2 and B=4.

So let's use the difference of squares formula A%5E2-B%5E2=%28A%2BB%29%28A-B%29 to factor the expression:

A%5E2-B%5E2=%28A%2BB%29%28A-B%29 Start with the difference of squares formula.

%289x%5E2%29%5E2-%284%29%5E2=%289x%5E2%2B4%29%289x%5E2-4%29 Plug in A=9x%5E2 and B=4.

So this shows us that 81x%5E4-16 factors to %289x%5E2%2B4%29%289x%5E2-4%29.

In other words 81x%5E4-16=%289x%5E2%2B4%29%289x%5E2-4%29.

Now let's factor 9x%5E2-4 further

-------------------------------------

9x%5E2-4 Start with the given expression.

%283x%29%5E2-4 Rewrite 9x%5E2 as %283x%29%5E2.

%283x%29%5E2-%282%29%5E2 Rewrite 4 as %282%29%5E2.

Notice how we have a difference of squares A%5E2-B%5E2 where in this case A=3x and B=2.

So let's use the difference of squares formula A%5E2-B%5E2=%28A%2BB%29%28A-B%29 to factor the expression:

A%5E2-B%5E2=%28A%2BB%29%28A-B%29 Start with the difference of squares formula.

%283x%29%5E2-%282%29%5E2=%283x%2B2%29%283x-2%29 Plug in A=3x and B=2.

So this shows us that 9x%5E2-4 factors to %283x%2B2%29%283x-2%29.

In other words 9x%5E2-4=%283x%2B2%29%283x-2%29.

----------------------------------------------------------------

Answer:

So 81x%5E4-16 completely factors to %289x%5E2%2B4%29%283x%2B2%29%283x-2%29

3 0

3 years ago

Simplifying rational expressions

Sonbull [250]

1. $\frac{(c + 8)(c - 8)}{(c - 8)(c + 3)}_,_$
   $\frac{c + 8}{c + 3}_,_$

2. $\frac{n^{2} + 4n - 12}{n^{2} + 2n - 8}_,_$
   $\frac{n^{2} + 6n - 2n - 12}{n^{2} + 4n - 2n - 8}_,_$
   $\frac{n(n) + n(6) - 2(n) - 2(6)}{n(n) + n(4) - 2(n) - 2(4)}_,_$
   $\frac{n(n + 6) - 2(n + 6)}{n(n + 4) - 2(n + 4)}_,_$
   $\frac{(n - 2)(n + 6)}{(n - 2)(n + 4)}_,_$
   $\frac{n + 6}{n + 4}_,_$

3. $\frac{42x^{2}y^{3}}{28x^{3}y}_,_$
   $\frac{3y^{2}}{2x}_,_$

4. $\frac{m^{2} - 3m - 10}{m - 5}_,_$
   $\frac{m^{2} - 5m + 2m - 10}{m - 5}_,_$
   $\frac{m(m) - m(5) + 2(m) - 2(5)}{m - 5}_,_$
   $\frac{m(m - 5) + 2(m - 5)}{m - 5}_,_$
   $\frac{(m + 2)(m - 5)}{m - 5}_,_$
   $m + 2_,_$

3 0

3 years ago

In a fitness program, Pedro does 20 sit-ups on the first day, and increases this by 2 sit-ups everyday. Determine the day when t

Fittoniya [83]

Answer:

day 540

Step-by-step explanation:

He increases his number of situps by 2 each day meaning on day 1 he'd do 2 extra, on day 2 he'd do 4 extra, on day he'd do 6 extra etc. We can show this by saying +2x where x is the day he is on. Then since he started with 20 we have to add 20 so it would be 20+2x. We want to know what day it is when he does 1100 situps so we can set our equation equal to 1100 and solve for X which is the day it would be.

20+2x=1100

2x=1080

I hope this helps and please don't hesitate to ask if there is anything still unclear!

x=540

5 0

3 years ago

An arithmetic sequence is defined by the general term tn = -5 + (n - 1)78, where n ∈N and n ≥ 1. What is the recursive formula o

GrogVix [38]

$\text{The general term of an arithmetic sequence:}\ a_n=a_1+(n-1)d\\\\a_n-n-th\ term\\a_1-first\ term\\d-common\ difference\\\\\text{We have}\ t_n=-5+(n-1)78.\ \text{Therefore}\ t_1=-5\ \text{and}\ d=78\\\\\text{The recursive formula of the sequence:}\\\\\left\{\begin{array}{ccc}t_1=-5\\t_n=t_{n-1}+78\end{array}\right$

5 0

3 years ago