To find the final mass of the solid, you can subtract the change in mass from the initial mass.
The initial mass is 260 grams, and the change in mass is -84 grams.
Final mass = Initial mass + Change in mass
Final mass = 260 grams + (-84 grams)
Final mass = 260 grams - 84 grams
Final mass = 176 grams
So, the final mass of the solid is 176 grams.