Which of the fallowing is an incorrect way to label the line in the diagram below

Abarbecue sold 26 hamburgers and hot dogs. hamburgers sell for $3.50 each and hot dogs sell for $2.00 each. if the barbecue made $70 in sales, determine and state the number of hot dogs sold.

Which equation represents the function on the graph?

If 2(a^2+b^2)=(a+b)^2 then, > a+b=0, > ab=0, > a=b, > 2a=b