How do i solve -16 + (-28)

Acourgette seed and a pumpkin seed is planted p(courgette seed germinates) 4/5 and p(pumpkin seed germinates) = 1/6 what is the probability that both seds germinate

Iam at home. /: i am playing video games. translate the following statement into symbolic form.

Prove sin2a + cos2a - 1 / sin2a + cos2a + 1 = 1 - tana / 1 + cota