Answer :
The dimensions of the rectangle are 6 and 3.5 ft.
Let the width of rectangle be x. So, the length of the rectangle will be 2x - 1. As per the known fact, the area of rectangle is given by the formula -
Area = length × breadth
Keep the values in formula to find the dimensions of the rectangle
x(2x - 1) = 21
Performing multiplication on Left Hand Side of the equation
2x² - x = 21
Rewriting the equation
2x² - x - 21 = 0
On factorizing we get, x = -3 and 3.5.
The dimensions of rectangle can not be negative, this, taking the value of x as 3.5. Now, the width of rectangle will be 3.5.
Length of rectangle = (2×3.5 - 1)
Length of rectangle = 7 - 1
Length of rectangle = 6
Thus, the length and width is 6 and 3.5 ft respectively.
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The complete question is -
the length of a rectangle 1ft less than double the width ,and the area of the rectangle is 21ft^2 find the dimensions