First, we will sue the distributive property to remove the parentheses. The term outside the parentheses is -4, so that is what we multiply the insides by.

3x-8x+20=15

We combine our like terms (our x-values).

-5x+20=15

We subtract 20 from both sides.

-5x=-5

We divide both sides by -5.

x=1

Have a wonderful day and keep on learning! :D

3 0

3 years ago

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Quality control is an important issue at ACME Company which manufacturers light bulbs. In order to conduct testing of the life h

mrs_skeptik [129]

Answer: 3424.28

Step-by-step explanation:

Given data : 378, 361, 350, 375, 200, 391, 375, 368, 321

Number of data values = 9

Mean : $\overline{x}=\dfrac{\sum^n_{i=1} x_i}{n}$

$\\\\=\dfrac{378+361+350+375+200+391+375+368+321}{9}\\\\=\dfrac{3119}{9}\approx346.56$

Variance = $\dfrac{\sum^n_{i=1} (x_i-\overline{x})^2}{n-1}$

$\sum^n_{i=1} (x_i-\overline{x})^2 = (31.44)^2+(14.44)^2+(3.44)^2+(28.44)^2+(-146.56)^2+(44.44)^2+(28.44)^2+(21.44)^2+(-25.56)^2\\\\=27394.2224$

Variance = $\dfrac{27394.2224}{8}=3424.2775\approx3424.28$

4 0

3 years ago