True and False and why please help with all five

5) To help assess how well a manager has controlled costs, actual costs should be compared to what the costs should have been for the actual level of activity.

6) Fixed costs should usually be included in performance reports because fixed costs are generally controllable.

7) Using a flexible budget, actual results can be compared to what costs should have been at the actual level of activity.

8) Fixed costs should not be included in a flexible budget because they do not change when the level of activity changes.

9) Actual costs are determined by plugging the actual level of activity for the period into the cost formulas used in flexible budgets.

10) Fixed costs should not be ignored when evaluating how well a manager has controlled costs.