Consider the motion towards right as positive and motion towards left as negative.
m₁ = mass of the cart moving to right = 0.500 kg
v₁ = initial velocity before collision of the cart moving towards right = 2.2 m/s
m₂ = mass of cart moving to left = 0.800 kg
v₂ = initial velocity before collision of the cart moving towards left = - 1.1 m/s
initial momentum of the system of carts before the collision is given as
P₁ = m₁ v₁ + m₂ v₂
P₁ = (0.500) (2.2) + (0.800) (- 1.1)
P₁ = 0.22 kg m/s
P₂ = momentum of system of carts after collision
As per conservation of momentum,
Momentum of system of carts after collision = Momentum of system of carts before collision
P₂ = P₁
P₂ = 0.22 kg m/s