What does 4r+6 represent in the expression

One line passes through (-7,-4) and (5,4) . another line passes through the point (-4,6) and (6,-9)

Ana earns 2.5% simple interest on $2,000 in her savings account. she does not make any deposits or withdrawals. after 3 years, how much interest will ana have earned on her savings account?

Emmanuel added 888 links per minute to his chain mail. allesia started 202020 minutes after emmanuel and added 131313 links per minute to her chain mail. how long had emmanuel worked when allesia caught up to him, and how many links had he added?