SOLUTION: a football field is about 50 yards wide by 120 yards long. the border of uniform width around the entire field has an area of about 1800 square yards. how wide is the border arou

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Question 302543: a football field is about 50 yards wide by 120 yards long. the border of uniform width around the entire field has an area of about 1800 square yards. how wide is the
border around the field?
do yu think yu can help me

Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
area of field ___ 50 * 120 = 6000

area of field and border ___ 6000 + 1800 = 7800

width of field and border ___ 50 + 2b (border on BOTH sides)

length of field and border ___ 120 + 2b (border on BOTH ends)

(50 + 2b)(120 + 2b) = 7800 ___ 6000 + 340b + 4b^2 = 7800

4b^2 + 340b - 1800 = 0 ___ b^2 + 85b - 450 = 0

factoring ___ (b + 90) (b - 5) = 0

b = 5

b = 90 not realistic