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3241004551 [841]
3 years ago
5

A particular chemistry book costs $6 less than a particular physics book, while two such chemistry books and three such physics

books cost a total of $123. Construct two simultaneous equations and solve them using the substitution method.
Mathematics
1 answer:
sladkih [1.3K]3 years ago
3 0

Answer:

Step-by-step explanation:

Let's say the Physics book costs $x

The Chemistry book will cost $x - $6

Two such Chemistry books will cost;

2($x - $6) = $(2x - 12)

Three such Physics books cost $3x

$(2x - 12) + $3x = $123

$5x - $12 = $123

$5x = $111

x = $22\frac{1}{5}

So the Physics book costs;  $22\frac{1}{5}

and the Chemistry book costs  $22\frac{1}{5} - 6 =  $16\frac{1}{5}

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For the equation, decide if it is always true or never true.<br><br> x + 1/2 = x − 1/2
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Answer:

Step-by-step explanation:

its false

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Suppose the number of insect fragments in a chocolate bar follows a Poisson process with the expected number of fragments in a 2
leonid [27]

Answer:

a)The expected number of insect fragments in 1/4 of a 200-gram chocolate bar is 2.55

b)0.6004

c)19.607

Step-by-step explanation:

Let X denotes the number of fragments in 200 gm chocolate bar with expected number of fragments 10.2

X ~ Poisson(A) where \lambda = \frac{10.2}{200} = 0.051

a)We are supposed to find the expected number of insect fragments in 1/4 of a 200-gram chocolate bar

\frac{1}{4} \times 200 = 50

50 grams of bar contains expected fragments = \lambda x = 0.051 \times 50=2.55

So, the expected number of insect fragments in 1/4 of a 200-gram chocolate bar is 2.55

b) Now we are supposed to find the probability that you have to eat more than 10 grams of chocolate bar before ending your first fragment

Let X denotes the number of grams to be eaten before another fragment is detected.

P(X>10)= e^{-\lambda \times x}= e^{-0.051 \times 10}= e^{-0.51}=0.6004

c)The expected number of grams to be eaten before encountering the first fragments :

E(X)=\frac{1}{\lambda}=\frac{1}{0.051}=19.607 grams

7 0
3 years ago
What is the first step in solving x^2+2x+3=0
Westkost [7]
First subtract three from both sides. then you have x^{2} +2x=-3 and you solve from there
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Simplify <br> a)3/7×28/15÷14/5<br> b)7/8+1/16-1/12
netineya [11]

Answer:

a)2/7

b)41/48

<em />

<em>Step-by-step explanation:</em>

<u>-Question A-</u>

1) Rephrase the problem to look like this:

3/7*28/15*5/14 <-- when dividing fractions you actually multiply by the reciprocal (opposite)

2) Multiply across the above phrase:

420/1470

3) Simplify your fraction:

2/7

There is nothing else to be done with 2/7 and thus it is your final answer.

<u></u>

<u>-Question B-</u>

1) Get the denominator of all 3 fractions to the same Least Common Denominator (48):

42/48 + 3/48 - 4/48

2) Do the arithmetic in the phrase above:

41/48

41/48 cannot be simplified and thus is your final answer

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3 years ago
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AleksandrR [38]
I’m pretty sure all you have to do is plug in your numbers for example number 5 is y=2x-2 so you would plug in the first number which is -1. So the equation that you solve would be y=2 times -1 minus 2. That would be -4. I hope this helps. If you need further explanation please say so in comments.
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