If (3a + 3b + 1) (3a + 3b - 1) = 80, then a + b = ?

What is the binomial expansion of (2x-3)^5

Josh has a rewards card for a movie theater he receives 15 points for becoming a rewards card holder he earns 3.5 points for each visit to the movie theater he needs at least 55 points to earn a free movie ticket which inequality can josh use to determine x, the minimum number of visits he needs to earn his first free movie ticket.

Prove that quadrilateral is a rhombus.