I need to solve for a and b

Aline passes through 3,7 and 6,9 what equation represents the line

See attachment below and find the equivalent of tan(∠qsr)

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236