6a+ -12a plz explain (a=1/2) i don't know evaluating expressions

Find the area of an equilateral triangle with a side of 6 inches

Joanie watched 1 out of three of a movie in the morning

How many heads would you expect if you flipped a coin twice? first, fill in the table below with the correct probabilities. hint: the sample space for flipping a coin twice is {hh, ht, th, tt}. a = b = c = f