How can you tell when a quadratic equation has two identical, rational solutions?

Ateacher has $80 to buy workbooks. each work book cost $3. if she buys as many workbooks as possible, how much money does she have leftover? a) $2 b) $4 c) $6 d) $8

Find the slope of the line below . enter your answer as a fraction or decimal. use a slash mark ( / ) as the fraction bar if necessary

Ineeeeed this is due tomorrow and i dont know the answer can you find all the exponents