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ki77a [65]
3 years ago
9

The length of a rectangular floor is 4 feet longer than its width w. The area of the floor is 525 ft^2.

Mathematics
2 answers:
andre [41]3 years ago
7 0

Answer:

  • 525 = (w+4)(w)
  • 21 ft by 25 ft

Step-by-step explanation:

Let w represent the width of the floor. Then the length of the floor is (w+4) and its area is ...

  A = LW

  525 = (w+4)(w)

  w^2 +4w -525 = 0

  (w -21)(w +25) = 0 . . . . factor the above

Solutions are ...

  w = 21, w = -25

We are interested in the positive solution: w = 21.

The floor is 21 feet wide and 25 feet long.

_____

<em>Alternate solution</em>

Sometimes, when the factors aren't obvious, it works well to write an equation for the average of the dimensions. Here, we can represent that with x, and use (x-2) for the width, and (x+2) for the length. Then we have ...

  525 = (x-2)(x+2) = x^2 -4

  529 = x^2

  √529 = 23 = x

Then w=23 -2 = 21, and the length is w+4 = 25.

Semmy [17]3 years ago
7 0

Answer:

x = 21

x= -25

Step-by-step explanation:x^2+4-525=0

               x^21x+25x-525=0

           x{_x^2__ - __3.7__) +5^2 (_5^2.x___ -  _3.5^2.7____)

                  x                x                     5^2                   5^2

          x(x^2-1-(3.7))+5^2(x-(3.7))=0

             x(x-27)+5^2(x-21)=0

          (x-21)((x(_x-21_)  + _5^2(x-21)_)=0

                       x-21               x-21

(x-21)(x+5^2)=0

(x-21)(x+25)=0

x- 21 =0

x+25= 0

x-21+21=21

(x+25)-25=-25

x=21

x+25-25=-25

x= 21

x= -25

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