Which of the following situations involve opposite quantities combine to make 0?

Dylan and dusty plan to take weekly surfing lessons together. if the 2-hour lessons are $20 per person and they plan to spend $100 each on new surfboards, what is the maximum number of lessons the two can take if the total amount spent for lessons and surfboards is at most $480?

Find the solution set of this inequality. enter your answer in interval notation using grouping symbols. |8x-4| ≤ 12

What is the volume of a cone with a height of 6 cm in the radius of 2 cm