Which of these is a correct expansion of (3x − 1)(4x² + 5)?

30 points! PLS HELP IF U SMART

ANTONII [103]

Answer:

y = 40 x = 80

Step-by-step explanation:

520 = 3.25x + 6.5y and x+y=120

x+y=120

x = 120-y

520 = 3.25(120-y)+6.5y

520 = 390-3.25y+6.5y

520 = 390+3.25y

130=3.25y

40 = y

x = 120-y

x = 120-(40)

x = 80

here's a graph

8 0

2 years ago

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Need help asap, thanks!!!ヾ(⌐■_■)ノ♪

Lelu [443]

Step-by-step explanation:

the probability of making one shot is 75% or 0.75 or 3/4.

the probability to make 2 shots is then

3/4 × 3/4 = 9/16 = 0.5625

and so on.

the probability to miss 1 shot is then 25% or 0.25 or 1/4.

the probability to make at least 4 out of 5 shots is the sum of the probability to make all 5 shots plus the probability to make 4 shots.

or the probability to miss 0 plus the probability to miss 1 shot.

anyway, we can go with the positive approach. it seems to be the same complexity as the negative approach.

the probability to make all 5 shots is

(3/4)⁵ = 3⁵/4⁵ = 243 / 1024 = 0.237304688...

the probability to e.g make the first 4 shots and miss the 5th is

(3/4)⁴×1/4 = 3⁴/4⁵ = 81 / 1024 = 0.079101563...

how many possibilities do we have to make 4 out of 5 shots ?

there is no repetition, and the sequence inside the "picked" 4 does not matter, so we need combinations :

C(5,4) = 5! / (4! × (5-4)!) = 5

so, the probability to make exactly 4 out 5 shots is

81/1024 × 5 = 405/1024 = 0.395507813...

and the total probability to make at least 4 shots is

243/1024 + 405/1024 = 648/1024 = 81/128 = 0.6328125

to control,

this plus making exactly 3 plus exactly 2 plus exactly 1 plus none must be the probability 1 (as there is no other possible outcome).

making 3 :

(3/4)³×(1/4)² = 3³/4⁵ = 27/1024

C(5,3) = 5×2 = 10

270/1024

making 2 :

3²/4⁵ = 9/1024

C(5,2) = 5×2 = 10

90/1024

making 1 :

3/1024

C(5,1) = 5

15/1024

making 0 :

1/1024

in sum

(270+90+15+1)/1024 = 376/1024

plus the 648/1024 = 1024/1024 = 1

correct.

4 0

2 years ago

The manager wants to advertise that anybody who isn't served within a certain number of minutes gets a free hamburger. But she d

aksik [14]

Answer:

The number of minutes advertisement should use is found.

x ≅ 12 mins

Step-by-step explanation:

(MISSING PART OF THE QUESTION: AVERAGE WAITING TIME = 2.5 MINUTES)

For such problems, we can use probability density function, in which probability is found out by taking integral of a function across an interval.

Probability Density Function is given by:

$f(t)=\left \{ {{0 ,\-t$

Consider the second function:

$f(t)=\frac{e^{-t/\mu}}{\mu}\\$

Where Average waiting time = μ = 2.5

The function f(t) becomes

$f(t)=0.4e^{-0.4t}$

The manager wants to give free hamburgers to only 1% of her costumers, which means that probability of a costumer getting a free hamburger is 0.01

The probability that a costumer has to wait for more than x minutes is:

$\int\limits^\infty_x {f(t)} \, dt= \int\limits^\infty_x {}0.4e^{-0.4t}dt$

which is equal to 0.01

Solve the equation for x

$\int\limits^{\infty}_x {0.4e^{-0.4t}} \, dt =0.01\\\\\frac{0.4e^{-0.4t}}{-0.4}=0.01\\\\-e^{-0.4t} |^\infty_x =0.01\\\\e^{-0.4x}=0.01$

Take natural log on both sides

$ln (e^{-0.4x})=ln(0.01)\\-0.4x=ln(0.01)\\-0.4x=-4.61\\x= 11.53$

<h3>Results</h3>

The costumer has to wait x = 11.53 mins ≅ 12 mins to get a free hamburger

3 0

3 years ago

What is the experamental probability that the coin lands on heads?

sammy [17]

Answer:

The experamental probability that the coin lands on head is 50 %

Step-by-step explanation:

Given:

Experiment:

A coin is Toss

Let the Sample Space be 'S' that is total number of outcomes for a coin has been tossed = { Head, Tail }

∴ n ( S ) = 2

Let A be the event of getting a Head on tossing a coin i.e { Head }

∴ n( A ) = 1

Now,

$\textrm{Probability} =\frac{\textrm{outcomes for the experiment}}{\textrm{total number of outcomes}}$

Substituting the values we get

$P(A) = \frac{n(A)}{n(S)} \\\\P(A) = \frac{1}{2} \\\\P(A) = 0.5\\\\P(A) = 50\%$

The experamental probability that the coin lands on head is 50 %

5 0

3 years ago

Assuming log, 4.4 = 1.4816 and log 7.7 = 2.0142, then whats the value of log, 7/4

denis23 [38]

Log (7/4) is equivalent to log (7.7/4.4), therefore it's log(7.7) - log(4.4), or...

2.0142 - 1.4816 = 0.5326

4 0

3 years ago

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