Let mass be:

m1=0.100 kg
m2=0.300 kg
m3=0.500 kg
(a.)Compute for the acceleration of the system if the table is frictionless.
(b.)Compute the acceleration of the system if the coefficient of the friction between the m2 and the table is 0.400.

You can't compute acceleration without knowing the force, F. Is there a pulley somewhere?

It is unclear what is meant by "the system". You need to provide a description of the system of threee masses. Your question probably came with a Figure.

Try using Newton's law,
F = m a.
"a" is the acceleration.
Someone will be glad to critique your work.

To compute for the acceleration of the system, we need to consider the forces acting on each mass and apply Newton's second law, which states that the net force acting on an object is equal to the mass of the object multiplied by its acceleration (F = ma).

(a) Frictionless table:
In this case, there is no friction force acting on the system. Thus, the only external force acting on the system is the force of gravity.

- Mass m1:
The force acting on m1 is its weight, which can be calculated by multiplying its mass by the acceleration due to gravity (g = 9.8 m/s^2).
F1 = m1 * g

- Mass m2:
The force acting on m2 is its weight (m2 * g) and the tension in the string (T) connecting m2 to m1. The tension in the string is equal to the force required to accelerate m2, which is also the force that accelerates m1.
F2 = m2 * g + T

- Mass m3:
The force acting on m3 is its weight (m3 * g) and the tension in the string (T) connecting m3 to m2. The tension in the string is equal to the force required to accelerate m3, which is also the force that accelerates m2.
F3 = m3 * g + T

Since the string connecting the masses is assumed to be massless and inextensible, the tension in the string is the same at all points.

- Net force on m1:
The net force acting on m1 is the tension in the string (T) pulling it to the right.
Fnet1 = T

- Net force on m2:
The net force acting on m2 is the tension in the string (T) pulling it to the right, minus its weight.
Fnet2 = T - m2 * g

- Net force on m3:
The net force acting on m3 is its weight (m3 * g) pulling it down, minus the tension in the string (T) pulling it up.
Fnet3 = m3 * g - T

Now we equate the net force with the product of each mass and acceleration:
Fnet1 = m1 * a
Fnet2 = m2 * a
Fnet3 = m3 * a

Since the tension in the string is the same for all masses, we can equate the net forces in terms of T:
Fnet1 = Fnet2 = Fnet3

Solving these equations will give us the value of the acceleration for the system.

(b) Coefficient of friction between m2 and the table:
In this case, we have an additional force of friction acting on mass m2. Using the equation F_friction = μ * N, where μ is the coefficient of friction and N is the normal force, we can calculate the force of friction (F_friction = μ * m2 * g).

We use the same approach as in (a) but include the force of friction as an external force acting on m2. The force of friction opposes the motion and needs to be subtracted from the net force acting on m2.

Fnet2 = T - m2 * g - F_friction

Solving these equations with the given values of masses and coefficients of friction will yield the acceleration for the system.

Please provide additional details about the system or the figure to proceed with the calculations.