the area of a rectangle is 21ft squared and the length is 1ft less than twice the width. find the dimensions.
we know that
The area pf rectangle is equal to
A=L*W
where
L is the length and W is tghe width
we have that
A=21 ft^2
so
21=LW ------> equation A
and
L=2W-1 -----> equation B
substitute equation B in equation A
21=(2W-1)W
solve for W
21=2W^2-W
2W^2-W-21=0
Solve the quadratic equation by graphing
see the attached figure
please wait a minute
W=3.5 ft
Find the value of L
L=2W-1
L=2(3.5)-1
L=6 ft
therefore
the dimensions of rectangle are 6 ft by 3.5 ft