Help me with this please

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?

Show your workcan a right triangle have this sides? *how to prove it without using the pythagorean theorema*

Lines a and b are parallel. what is the value of x? -5 -10 -35 -55