Answer:



Step-by-step explanation:
Given

Required
Select 3 equivalent expressions

Express 9 as 3^2
--- This is one equivalent expression
Take
as difference of two squares
-- This is another equivalent expression:
Solving further:
becomes
-- This is another equivalent expression:
Hence, the equivalent expressions are:



The motion of the mass as it moves on the bottom of the spring is a
repetitive motion.
Reasons:
The general form of the equation of the simple harmonic motion of the
mass is <em>d</em> = a·sin(ω·t)
Where;
d = The distance of the mass from the rest position
a = The maximum displacement of the mass from the equilibrium position = 6 cm
ω = The frequency of rotation
t = The time of motion
ω = The frequency of rotation

Where;
T = The time to complete one cycle (the period of oscillation) = 4 seconds

Combining the above values gives the modelling equation as follows;

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