Problem 1. Look for the mirror lines. They form a system of squares with the 90-degree centers in the centers of the squares. Then there are glide reflections and half turns in exactly the same pattern as the lab 11/28.
Problem 6. (a) Look up the definition. (b) Draw the figure and you will get a right triangle with the invariant line being the perpendicular bisector of one leg. The problem is to prove that this line passes through the midpoint of the hypotenuse. This problem has come up before in labs, homework and earlier tests.
Problem 7. (a) The composition is a rotation by 180 + 60 = 240 degrees, which is the same as -120 degrees. (b) Construct the center C as shown in class or as shown in Brown, fig 2.25. You can try this out and either with Sketchpad or looking carefully at the shape of triangle ABC. From this you should be able to figure out where F takes points A, B, and especially, C.