Simplify this for me please

Which expression is equivalent to (5x^7+7x^8) − (4x^4−2x^8)? a. 9x^8 + 5x^7−4x^4 b. 3x^8 + 7x^7 c. 12x^8 − 2x^4 d. 5x^8 + 5x^7 + 4x^4

Ashley spent half of her lunch money on a turkey sandwich. then she spent two-thirds of the money she had left on a bottle of juice and the rest of the money on a cookie. if the cookie cost $.75, how much lunch money did ashley have to start with?

An animal shelter has fixed weekly expenses of $750. each animal is the shelter costs an additional $6 a week. during the summer months, the weekly expenses are at least $1170. write and solve an inequality that represents the number of animals at the shelter for expenses to be at least $1170 a week.