The measure of plz help

Can someone check if i did this correct. it’s number 4 if you’re wondering.

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

Aflower has 26 chromosomes. to create a new flower, how many chromosomes would a sperm cell have? what is this process called? part 2: within a flower cell that has 26 chromosomes, how many chromosomes would a cell that is created within the stem of a flower as it grows, have? what is this process called?