Please help I will really appreciate it it's about systems of equation

Factor the following expression. 27y3 – 343 a. (3y + 7)(9y2 + 2ly + 49) b. (3y – 7)(9y2 + 2ly + 49) c. (3y – 7)(932 – 217 + 49) d. (3y + 7)(92 – 2ly + 49)

Jon’s weight loss for each week of the month is 5 lbs., 2.5 lbs., and 2.5 lbs. he gained 3.5 lbs. the last week. if jon originally weighed 198 lbs., how much does he weigh now?

One cell phone plan charges $20 per month plus $0.15 per minute used. a second cell phone plan charges $35 per month plus $0.10 per minute used. write and solve an equation to find the number of minutes you must talk to have the same cost for both calling plans.