Brittany needs a total of 12 3/4 yards of yarn for a art project she needs 1 3/8 yards of blue yarn and 5 1/2 yards of green yarn the rest of the yarn she needs his red how much red yarn does britney need?

Britney will need 6 7/8 of red yarn.

We can model the equation:y = m x + b, where y is the total profit and x is the number of hotdogs sold.The system of equations is:
90 = 40 m + b210 = 80 m + bb = 90 - 40 m210 = 80 m + 90 - 40 m210 - 90 = 40 m120 = 40 mm = 120 : 40m = 3b = 90 - 40*3b = 90 - 120b = - 30 The equation is y = 3 x - 30