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Use PEMDAS (Parentheses, Exponents, Multipy/Divide, Add/Subtract):

2 + (4 + 2) ÷ 5 x 4 - 3²
P: 2 + (6) ÷ 5 x 4 - 3²
E: 2 + 6 ÷ 5 x 4 - 9
MD: 2 + \( \frac{6}{5} \) x 4 - 9
MD: 2 + \( \frac{24}{5} \) - 9
AS: \( \frac{10}{5} \) + \( \frac{24}{5} \) - 9
AS: \( \frac{34}{5} \) - 9
AS: \( \frac{34 - 45}{5} \)
\( \frac{-11}{5} \)
-2\(\frac{1}{5}\)

65% of the water consumption is industrial use and 31% is personal use so (65% - 31%) = 34% more water is used for industrial purposes. 20,000 gallons are consumed daily so industry consumes \( \frac{34}{100} \) x 20,000 gallons = 6,800 gallons.

First, solve for \( \left|b - 4\right| \):

\( \left|b - 4\right| \) - 6 = -6
\( \left|b - 4\right| \) = -6 + 6
\( \left|b - 4\right| \) = 0

The value inside the absolute value brackets can be either positive or negative so (b - 4) must equal + 0 or -0 for \( \left|b - 4\right| \) to equal 0:

So, b = 4 or b = 4.

A number in scientific notation has the format 0.000 x 10^exponent. To convert to scientific notation, move the decimal point to the right or the left until the number is a decimal between 1 and 10. The exponent of the 10 is the number of places you moved the decimal point and is positive if you moved the decimal point to the left and negative if you moved it to the right:

0.0001598 in scientific notation is 1.598 x 10^-4