In class, I wasn't paying attention and our teacher gave us problems like this: -2tg(-4θ)

I have no idea what (tg) is and what I need to do here, does anyone have any idea?

ratio is 2 : 9

the answer is three

13.5 : 3

- (2, -7)

- lines r and s and lines t and u must be parallel

this is a direct variation proportion. y = kx

y is the total amount due, k is the constant of variation, and x is the number of texts sent.

plug in the 3.20 and the 16 to solve for the "k". this is the constant of proportionality. it is the value that will not change.

3.20 = k(16). solving you get $.20 per text.

the equation would then be y = .20x