Can you please help me with the highlighted questions or explain how to solve? Thank you

Randy and trey take turns cleaning offices on the weekends. it takes randy at most 4 hours to clean the offices. it takes trey at most 6 hours to clean the offices. what is the greatest amount of time it would take them to clean the offices together? 2.4 hours 2.5 hours

Rena used the steps below to evaluate the expression , when . step 1: substitute into the expression. step 2: simplify the parentheses. step 3: evaluate the power to a power. step 4: use reciprocals and find the value. in which step did rena make the first error?

11 12 triangle abc is congruent to triangle fde, and both triangles have the same orientation, as shown. what is the slope of df, which is also the slope of ac?