Step-by-step explanation:
It is given that,
Spring constant, k = 81 N/m
We need to find the force required to :
(a) Compress the spring by 6 cm i.e. x₁ = 6 cm = -0.06 m
It can be calculated using Hooke's law as :
F = - k(-x₁)

F = 4.86 N
(b) Expand the spring by 17 cm i.e. x₂ = 17 cm = +0.17 m
So, F = -kx₂

F = -13.77 N
Hence, this is the required solution.