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

5 + (2 + 3) ÷ 4 x 4 - 5²
P: 5 + (5) ÷ 4 x 4 - 5²
E: 5 + 5 ÷ 4 x 4 - 25
MD: 5 + \( \frac{5}{4} \) x 4 - 25
MD: 5 + \( \frac{20}{4} \) - 25
AS: \( \frac{20}{4} \) + \( \frac{20}{4} \) - 25
AS: \( \frac{40}{4} \) - 25
AS: \( \frac{40 - 100}{4} \)
\( \frac{-60}{4} \)
-15

To add or subtract terms with exponents, both the base and the exponent must be the same. In this case they are so subtract the coefficients and retain the base and exponent:

8y⁴ - 4y⁴
(8 - 4)y⁴
4y⁴

There are 4 2-passenger taxis available so that's 4 x 2 = 8 total seats. There are 12 people needing transportation leaving 12 - 8 = 4 who will have to find other transportation.

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:

6,664,000 in scientific notation is 6.664 x 10⁶

To add these distances, they must share the same unit so first you need to first convert the swim distance from meters (m) to kilometers (km) before adding it to the bike and run distances which are already in km. To convert 100 meters to kilometers, divide the distance by 1000 to get 0.1km then add the remaining distances:

total distance = swim + bike + run
total distance = 0.1km + 20.6km + 7.5km
total distance = 28.2km