How do you work out 9 + (-4) - 6 ? make it detailed

Given: m∠ adb = m∠cdb ad ≅ dc prove: m∠ bac = m∠bca lol

Ariel is working at a meat packing plant for 5 nights a week. her regular wage is $11 an hour. she earns tine and a half for any overtime hours. this week she worked 9 hours of over time .how much will ariel earn for overtime this week ?

Random variables x poisson~ ( a) ,y poisson ~ ( a) . x and y are independent. if 2 1, 2 1. u =2x+ y-1, v=2x- y +1. find: ) cov (u ,v ).