SOLUTION: A landscaper wants to enclose a 90ft by 120ft rectangle with a walk of uniform width. He wants to use a supply of crushed rock that will cover 1744 square feet of walk. How wide sh

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Question 151750: A landscaper wants to enclose a 90ft by 120ft rectangle with a walk of uniform width. He wants to use a supply of crushed rock that will cover 1744 square feet of walk. How wide should he make the walk?
Answer by checkley77(12844) About Me  (Show Source):
You can put this solution on YOUR website!
90*120=10,800ft^2 for the rectangle.
(90+2x)(120+2x)=10,800+1744
10,800+240x+180x+4x^2=12,544
4x^2+420x+10,800-12,544=0
4x^2+420x-1,744=0
4(x^2+105x-436)=0
(x+109)(x-4)=0
x-4=0
x=4 ft is the width of the walk.
proof:
(90+2*4)(120+2*4)=12,544
98*128=12,544
12,544=12,544