Could I please get some help on these two questions?

Find the sum of 4x^{2} -4+6 and -7^{2} +3x+1

An episode of a television show is 60 minutes long when it originally airs with commercials. on a dvd without commercials, the episode is only 417 minutes long. how many1-minute commercials did the episode include when it originally aired? write and solve an equation to justify your answer.

Idont understand math at all! : o( use this scenario to answer the remaining questions: brenton purchased a new bedroom set for $4,500.00. he lives in arizona and pays a 8.75% sales tax. if he made a 50% down payment and financed the rest, what amount did he finance? what is the total sales tax brenton will pay? enter your answer in currency format, round to the nearest cent. what was brenton's total amount financed? enter your answer in currency format, round to the nearest cent.