PART A:
Scientific notation is given by A×10ⁿ where A is any number in a unit and 'n' is an integer.
0.000025 = 2.5×10⁻⁵
PART B:
Diameter of grain of sand ÷ Diameter of human body average cell
(2×10⁻⁴) ÷ (1×10⁻⁵)
(2÷1) × (10⁻⁴÷10⁻⁵)
2 × (10⁻⁴ ⁻ ⁻⁵) = 2 × 10⁽⁻⁴⁺⁵⁾ = 2 × 10¹ = 20 times bigger
PART C:
The diameter of human body's average cell in nanometer
1 × 10⁻⁵ metre = 1 × 10⁻⁵ × 10⁹ = 1 × 10⁽⁻⁵⁺⁹⁾ = 1 × 10⁴ nanometer
PART D:
Smallest bacteria = 300 nanometer
300 nm = 300 ÷ 10⁹ = (3 × 10²) ÷ 10⁹ = 3 × (10²⁻⁹) = 3 × 10⁻⁷ meter
PART E:
Laws of exponents that are applied in scientific notation is
xᵇ × xᵃ = x⁽ᵇ⁺ᵃ⁾
xᵇ ÷ xᵃ = x⁽ᵇ⁻ᵃ⁾
I will go about solving this using the elimination method.
First, convert the equations.
10x + y = -20
4x + y = -12
Second, find the easiest variable to get rid of and get rid of it! (In this case, y) We will subtract to get rid of y.
6x = -8
Third, you want to solve the equation.
6x = -8 (divide by 6)
x =

Fourth, solve for y by inserting the answer for x into one of the equations.
10(

) + y = -20

+ y = -20 (subtract

)
y =

The solution for this system of equations is (

,

).
8.3 : anything multiplied by one is itself
Answer:
4
Step-by-step explanation: