What is the value of x?

Mathematics

1 answer:

alina1380 [7]3 years ago

6 0

3x/7 + 5/7 = 4/7

First, since the fractions carry the same denominator (luckily), we can easier combine the first two fractions, resulting in having to add the numerators.
$\frac{3x + 5}{7} = \frac{4}{7}$

Second, our next step is to multiply both sides by 7. Our goal is to get the variable (x) by itself on one side of the problem, so we have to do everything on the other side.
$3x + 5 = \frac{4}{7} \times 7$

Third, let's simplify 4/7 × 7. To do so, we multiply the whole number by the numerator. Basically, 7 × 4 = 28.
$3x + 5 = \frac{28}{7}$

Fourth, we can now simplify 28/7. To do this, we can ask ourselves, what can multiply into 7 to equal 28? 7 ÷ 28 = (4), so 4 is our answer for this.
$3x + 5 = 4$

Fifth, we can continue doing everything on one side. We will need to subtract 5 from each side.
$3x = 4 - 5$

Sixth, let's simplify 4 - 5, which is easily -1. Our problem will look like 3x = -1, but we have one more step to do. Our last step is to divide each side by 3. This will create a fraction. Our fraction will be negative because we carried our -1 over.
$x = - \frac{1}{3}$

Answer in fraction form: $\fbox {-1/3}$
Answer in decimal form: $\fbox {-0.3333}$

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We need at least 243 stores.

Step-by-step explanation:

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$\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}$

In which

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The margin of error of the interval is:

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95% confidence level

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n is found when M = 0.04. So

$M = z\sqrt{\frac{\pi(1-\pi)}{n}}$

$0.04 = 1.96\sqrt{\frac{0.886*0.114}}{n}}$