Sin 5xcos x - cos 5xsin x

Sal is tiling his entryway. the floor plan is drawn on a unit grid. each unit length represents 1 foot. tile costs $1.35 per square foot. how much will sal pay to tile his entryway? round your answer to the nearest cent.

Which one is true about the hexagons ?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.