Finding the mass of a block after colliding with a spring

1. The problem statement, all variables and given/known data

A block moves along a frictionless surface with an initial velocity of 10 m/s. It contacts a spring of spring constant 350 N/m. Underneath the spring at and after the point of contact the ground is rough and applies a constant friction force of 45 N. The spring compresses 0.75 m before the mass stops. What is the mass of the block?

2. Relevant equations

Ki + Ui = Kf + Uf

3. The attempt at a solution

Ui and Kf are zero, so I had 1/2mv2 = 45 + 1/2kx2, but I’m not sure where to put the friction force in the equation.
The answer is supposed to be 2.64 kg… Please help!

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