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3 years ago

Evaluate the expression xy-3x; when x=4 and y=5. Pls provide explanation. Will choose brainliest.

Mathematics

1 answer:

Iteru [2.4K]3 years ago

7 0

4*5-3*4

20-12

Just plug in the numbers and solve. Remember that you multiply before you subtract.

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Which variable will you choose to eliminate? How?

Inga [223]

Answer:

Variable elimination

8x+3y=-7
3y=-8x-7
y=-8/3x-7/3

Now plug it into y
7x-16/3x-14/3=-3
5/3x-14/3=-3
5/3x=5/3
x=1

4 0

3 years ago

does anyone know what 4/9 - 3/9 - 5/9 + 5 - 8 is simplified? if u do it would help me greatly. thank you.

AleksandrR [38]

Answer:

-3 4/9

Step-by-step explanation:

The fractions all have the same denominator, so are easily added.

Of course, you know how to add signed integers.

4/9 - 3/9 - 5/9 + 5 - 8

= (4 -3 -5)/9 +(5 -8)

= -4/9 -3

= -(3 4/9)

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3 years ago

How do I use a number line to find the indicated distance

anyanavicka [17]

2nd point distance-1st point distant

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3 years ago

(CO 3) Fifty-four percent of US teens have heard of a fax machine. You randomly select 12 US teens. Find the probability that th

11111nata11111 [884]

Answer:

a) $P(X=6)=(12C6)(0.54)^6 (1-0.54)^{12-6}=0.217$

b) $P(X> 8) = P(X\geq 9)= P(X=9)+P(X=10)+P(X=11)+P(X=12)$

$P(X=9)=(12C9)(0.54)^9 (1-0.54)^{12-9}=0.0836$

$P(X=10)=(12C10)(0.54)^{10} (1-0.54)^{12-10}=0.0294$

$P(X=11)=(12C11)(0.54)^{11} (1-0.54)^{12-11}=0.00628$

$P(X=12)=(12C12)(0.54)^{12} (1-0.54)^{12-12}=0.000615$

And adding the values we got:

$P(X> 8) = P(X\geq 9)= P(X=9)+P(X=10)+P(X=11)+P(X=12)= 0.0836+0.0294+0.00628+0.000615 = 0.120$

Step-by-step explanation:

Previous concepts

The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".

Solution to the problem

Let X the random variable of interest "number of teens that have heard of a fax machine", on this case we now that:

$X \sim Binom(n=12, p=0.54)$

The probability mass function for the Binomial distribution is given as:

$P(X)=(nCx)(p)^x (1-p)^{n-x}$

Where (nCx) means combinatory and it's given by this formula:

$nCx=\frac{n!}{(n-x)! x!}$

Part a

For this case we want this probability:

$P(X=6)=(12C6)(0.54)^6 (1-0.54)^{12-6}=0.217$

Part b

For this case we want this probability:

$P(X> 8) = P(X\geq 9)= P(X=9)+P(X=10)+P(X=11)+P(X=12)$

$P(X=9)=(12C9)(0.54)^9 (1-0.54)^{12-9}=0.0836$

$P(X=10)=(12C10)(0.54)^{10} (1-0.54)^{12-10}=0.0294$

$P(X=11)=(12C11)(0.54)^{11} (1-0.54)^{12-11}=0.00628$

$P(X=12)=(12C12)(0.54)^{12} (1-0.54)^{12-12}=0.000615$

And adding the values we got:

$P(X> 8) = P(X\geq 9)= P(X=9)+P(X=10)+P(X=11)+P(X=12)= 0.0836+0.0294+0.00628+0.000615 = 0.120$

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3 years ago

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