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vodka [1.7K]
2 years ago
11

Tommy was trying to solve the system of a linear equation and a quadratic equation shown below. 2x – y = –1 x2 – 5x – y = –7 Tom

my had completed the following steps in his algebraic solution process but could not factor the resulting quadratic, x2 – 7x – 1, to complete the problem. Step I: y = 2x + 1 Step II: x2 – 5x – (2x + 1) = –7 Step III: x2 – 5x – 2x – 1 = –7 Step IV: x2 – 7x – 1 = –7 Determine the step in which Tommy made his mistake and justify your reasoning.
Mathematics
1 answer:
drek231 [11]2 years ago
4 0

Answer:

Step IV; Tommy must set the quadratic expression equal to 0 before factoring.

plz give brainlyest

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We learned in that about 69.7% of 18-20 year olds consumed alcoholic beverages in 2008. We now consider a random sample of fifty
maw [93]

Answer:

(1) The expected number of people who would have consumed alcoholic beverages is 34.9.

(2) The standard deviation of people who would have consumed alcoholic beverages is 10.56.

(3) It is surprising that there were 45 or more people who have consumed alcoholic beverages.

Step-by-step explanation:

Let <em>X</em> = number of adults between 18 to 20 years consumed alcoholic beverages in 2008.

The probability of the random variable <em>X</em> is, <em>p</em> = 0.697.

A random sample of <em>n</em> = 50 adults in the age group 18 - 20 years is selected.

An adult, in the age group 18 - 20 years, consuming alcohol is independent of the others.

The random variable <em>X</em> follows a Binomial distribution with parameters <em>n</em> = 50 and <em>p</em> = 0.697.

The probability mass function of a Binomial random variable <em>X</em> is:

P(X=x)={50\choose x}0.697^{x}(1-0.697)^{50-x};\ x=0,1,2,3...

(1)

Compute the expected value of <em>X</em> as follows:

E(X)=np\\=50\times 0.697\\=34.85\\\approx34.9

Thus, the expected number of people who would have consumed alcoholic beverages is 34.9.

(2)

Compute the standard deviation of <em>X</em> as follows:

SD(X)=\sqrt{np(1-p)}=\sqrt{50\times 0.697\times (1-0.697)}=10.55955\approx10.56

Thus, the standard deviation of people who would have consumed alcoholic beverages is 10.56.

(3)

Compute the probability of <em>X</em> ≥ 45 as follows:

P (<em>X</em> ≥ 45) = P (X = 45) + P (X = 46) + ... + P (X = 50)

                =\sum\limits^{50}_{x=45} {50\choose x}0.697^{x}(1-0.697)^{50-x}\\=0.0005+0.0001+0.00002+0.000003+0+0\\=0.000623\\\approx0.0006

The probability that 45 or more have consumed alcoholic beverages is 0.0006.

An unusual or surprising event is an event that has a very low probability of success, i.e. <em>p</em> < 0.05.

The probability of 45 or more have consumed alcoholic beverages is 0.0006. This probability value is very small.

Thus, it is surprising that there were 45 or more people who have consumed alcoholic beverages.

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2 years ago
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Answer:

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2 years ago
At 1600 principal earns 7% interest compound semiannually twice per year after 33 years what is the balance in the account
NARA [144]
A $1,600.00 principle earns 7% interest, compounded semiannually twice per year. After 33 years, what is the balance in the account. My answer is $112,992.00

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3 years ago
T=pd/2x<br><br><br><br>solve for X<br><br>i always get confused when theirs more then one letter
Ainat [17]
When there's more than one letter, and you just have to solve for one variable, you can just solve it like you would any other equation. Treat the other variables like numbers and add, subtract, multiply, and divide them to both sides of the equation in order to isolate the variable you want to solve for.

t= \frac{pd}{2x}  \\  \\ t*2x= \frac{pd}{2x}*2x \\  \\ 2tx=pd \\  \\  \frac{2tx}{2t} = \frac{pd}{2t}  \\  \\ x=\frac{pd}{2t}
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2 years ago
Read 2 more answers
A man has two more nickels than dimes. He has $1.15 in all. How many coins of each kind does he have?
zhannawk [14.2K]

Answer:

Man has 9 Nickels and 7 dimes.

Step-by-step explanation:

Let Number of dimes be x

and Number of Nickels be y

As Per given data he has two more nickels than dimes.

y= 2+x\\

As we know that

1\$ = 100 cent

1 nickel is worth = 5 cents = \frac{5}{100}= 0.05\$

1 dime is worth = 10 cents = \frac{10}{100} 0 .1\ $

According to given data he has \$\ 1.15 total nickel and dimes

So the equation becomes,

0.05y+0.1x=1.15

but y= 2+x

0.05(2+x)+0.1x=1.15\\0.1+0.05x+0.1x=1.15\\0.1+0.15x= 1.15\\0.15x= 1.15-0.1\\0.15x=1.05\\x=\frac{1.05}{0.15}= 7

Substituting value of x in equation y = 2+x we get

y= 2+7 =9

Man has 9 Nickels and 7 dimes.

5 0
3 years ago
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