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Pool 20 feet long and 12 feet wide, how wide is the safety walkway if the walkway area 228
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Your equation is
(20 + 2x)*(12+2x) - 20*12 = 228,
where x is the width of the walkway in feet.
Left side is the difference of the areas of two rectangles.
Now simplify the equation:
= ,
= .
Reduce by the factor 4:
= .
Factor left side:
(x+19)*(x-3) = 0.
The roots are x = -19 and x = 3.
Only positive value does fit the condition.
Answer. The width of the walkway is 3 ft.