Given that a=4,b=2 and c=-1, find the value of a-b+c

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?

Prove that quadrilateral is a rhombus.

What is the quotient of m^6/5 ÷ 5/m^2? assume m does not equal pl