SOLUTION: Ref. Question 1046639: "(s + 5) (s - 4) = s^2 s^2 + s - 20 = s^2 s = 20ft for the Square" I don't understand these steps. Thanks.

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Question 1046667: Ref. Question 1046639:
"(s + 5) (s - 4) = s^2
s^2 + s - 20 = s^2
s = 20ft for the Square"
I don't understand these steps. Thanks.
Answer by MathLover1(20849) (Show Source):
You can put this solution on YOUR website!

given:
A square garden is to be enlarged to a rectangular by adding , to the length and deducting .
the area will be unchanged
to find: present and new dimensions
as you know, the area of a square is

Let = side of square
so, the area is ........eq.1
now you want to make a rectangle from that square by adding to the and the width reducing by
so, rectangle will have:
the length:
Width:
the area of rectangle will be:
...expand

.............eq.2
now we have:
A=s^2.............eq.1
A= s^2 + s -20.............eq.2
__________________________
since area is unchanged, left sides are equal; so, make equal right sides and solve for
.....move all terms from right to the left

so, when we have square, side length is
->present dimensions

and area is

when we make rectangle the length will be:
and
the width will be