4. (4 + 3i) (2 – 5i) a. 23 + 14i b. –7 – 14i c. 23 – 14i
d. 8 – 14i – 15i2
Solve each equation

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

Combine the information in the problem and the chart using the average balance method to solve the problem.

Events a and b are independent. the probability of a occurring is 2/5. the probability of b occurring is 1/4. what is p(a and b)?