Use the unit circle and the sum OR difference identity for cosine to prove that cos 180 = -1. Make sure to indicate whether you are using sum or difference
and write out the formula in your work

Solve the equation 3x2 + 19x + 9 = 0 to the nearest tenth.

Which of the following are parts of a sphere

Jack has a piece of red ribbon that is two times as long as his piece of blue ribbon. he says that he can use two different equation to find out how long his piece of red ribbon is compared to his piece of blue ribbon is. is he correct? explain his reasoning