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kherson [118]
3 years ago
8

would someone be able to explain to me how to solve these problems? I don't need the solutions, I just need an explanation. I ne

ed to solve the quadratic by factoring.

Mathematics
1 answer:
Leni [432]3 years ago
8 0
The first 3  are examples of the difference of 2 squares so you use the identity 
a^2 - b^2 = (a + b)(a - b)
x^2 - 49 = 0 
so (x + 7)(x - 7) = 0
so either x + 7 = 0 or x - 7 = 0
giving x = -7  and 7.
Number 7 reduces to 3x^2 =12, x^2  = 4 so x = +/- 2
Number 8  take out GCf (d) to give 
d(d - 2)  = 0   so d = 0 ,  2
9 and 10 are more difficult to factor
you use the 'ac' method  Google it to get more details
2x^2 - 5x + 2
multiply first coefficient by the constant at the end 
that is 2 * 2 =  4
Now we want  2 numbers  which when multiplied give + 4 and when added give - 5:-    -1 and -4  seem promising so we write the equation as:-

2x^2 - 4x - x + 2 = 0

now factor by grouping 
2x(x - 2) - 1(x - 2) = 0

(x - 2) is common so

(2x - 1)(x - 2) = 0
and 2x - 1 = 0 or x - 2 = 0  and now you can find x.

The last example is solved in the same way.


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Answer:

A is the answer

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Step-by-step explanation:

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3 years ago
1. The compound interest on $2500 for 5 years at 4% per annum<br> (compounded annually) is
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2 years ago
I rlly need help with this :(
kobusy [5.1K]

Using the normal distribution, it is found that:

a) The pilot is at the 72th percentile.

b) 19.13% of pilots are unable to fly.

<h3>Normal Probability Distribution</h3>

The z-score of a measure X of a normally distributed variable with mean \mu and standard deviation \sigma is given by:

Z = \frac{X - \mu}{\sigma}

  • The z-score measures how many standard deviations the measure is above or below the mean.
  • Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.

The mean and the standard deviation are given, respectively, by:

\mu = 72.6, \sigma = 2.7.

Item a:

The percentile is the <u>p-value of Z when X = 74.2</u>, hence:

Z = \frac{X - \mu}{\sigma}

Z = \frac{74.2 - 72.6}{2.7}

Z = 0.59

Z = 0.59 has a p-value of 0.7224.

72th percentile.

Item b:

The proportion that is able to fly is the <u>p-value of Z when X = 78 subtracted by the p-value of Z when X = 70</u>, hence:

X = 78:

Z = \frac{X - \mu}{\sigma}

Z = \frac{78 - 72.6}{2.7}

Z = 2

Z = 2 has a p-value of 0.9772.

X = 70:

Z = \frac{X - \mu}{\sigma}

Z = \frac{70 - 72.6}{2.7}

Z = -0.96

Z = -0.96 has a p-value of 0.1685.

0.9772 - 0.1685 = 0.8087 = 80.87%.

Hence the percentage that is unable to fly is:

100 - 80.87 = 19.13%.

More can be learned about the normal distribution at brainly.com/question/4079902

#SPJ1

3 0
2 years ago
1. Classify the polynomial 2x4 + 6x − 3 by number of terms. constant trinomial binomial cubic
goldenfox [79]
Polynomial are classified according to their number of terms. 5x^3+8y+6x^2 has three terms, 2xy has 1 term and 15-y^2. A polynomial with 1 term is called a monomial, A polynomial with 2 terms is called a binomial while a polynomial with 3 terms is called a trinomial. Thus our polynomial 2x^4+6x-3 is called a trinomial.
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3 years ago
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Step-by-step explanation:

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