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3 years ago

Can someone please solve this? a-3 Times a+7

Mathematics

2 answers:

Colt1911 [192]3 years ago

8 0

You have to combine like terms.
Answer: -2a+7

3241004551 [841]3 years ago

5 0

The answer is a^2+4a−21. use the foil technique. (First, Outer, Inner, Last)

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Which ordered pairs are solutions to the inequality 3x-4y>5

Sloan [31]

Note: you did not provide the answer options, so I am, in general, solving this query to solve your concept, which anyways would clear your concept.

Answer:

Please check the explanation.

Step-by-step explanation:

Given the inequality

$3x-4y>5$

All we need is to find any random value of 'x' and then solve the inequality.

For example, putting x=3

$3\left(3\right)-4y>5$

$9-4y>5$

$-4y>-4$

$\mathrm{Multiply\:both\:sides\:by\:-1\:\left(reverse\:the\:inequality\right)}$

$\left(-4y\right)\left(-1\right)$

$4y$

$\mathrm{Divide\:both\:sides\:by\:}4$

$\frac{4y}{4}$

$y$

So, at x = 3, the calculation shows that the value of y must be less

than 1 i.e. y<1 in order to be the solution.

Let us take the random y value that is less than 1.

As y=0.9 < 1

so putting y=0.9 in the inequality

$3\left(3\right)-4\left(0.9\right)$

$=9-3.6$

$=5.4$

As 5.4 > 5

Means at x=3, and y=0.9, the inequality is satisfied.

Thus, (3, 0.9) is one of the many ordered pairs solutions to the inequality 3x-4y>5.

6 0

3 years ago

Solve |x| < 13 A. {-13, 13} B. {x| -13< x < 13} C. {x|x < -13, x> 13}

Gemiola [76]

Answer:

the solution for x will be given by {x| -13 < x < 13}

Therefore the correct option is B.

Step-by-step explanation:

i) given that |x| < 13

ii) therefore x < 13 for positive values of x

iii) for negative values of x we have -x < 13

therefore x > -13

iv) from ii) and iii) above we can conclude that the solution for x will be given by {x| -13 < x < 13}

Therefore the correct option is B.

7 0

3 years ago

An article written for a magazine claims that 78% of the magazine's subscribers report eating healthily the previous day. Suppos

Schach [20]

Answer:

89.44% probability that less than 80% of the sample would report eating healthily the previous day

Step-by-step explanation:

We use the binomial approximation to the normal to solve this question.

Binomial probability distribution

Probability of exactly x sucesses on n repeated trials, with p probability.

Can be approximated to a normal distribution, using the expected value and the standard deviation.

The expected value of the binomial distribution is:

$E(X) = np$

The standard deviation of the binomial distribution is:

$\sqrt{V(X)} = \sqrt{np(1-p)}$

Normal probability distribution

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore of a measure X is given by:

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

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

When we are approximating a binomial distribution to a normal one, we have that $\mu = E(X)$ , $\sigma = \sqrt{V(X)}$ .