Can I get help with this question?

How do you use the additive inverse to evaluate an expression that uses subtraction in a full sentence

(b) suppose that consolidated power decides to use a level of significance of α = .05, and suppose a random sample of 100 temperature readings is obtained. if the sample mean of the 100 temperature readings is x⎯⎯ = 60.990, test h0 versus ha and determine whether the power plant should be shut down and the cooling system repaired. perform the hypothesis test by using a critical value and a p-value. assume σ = 5. (round your z to 2 decimal places and p-value to 4 decimal places.)

During a wright loss challenge your friend goes from 125 pounds to 100 pounds.what was the percent weight loss