The width of a rectangular slab of concrete is 3 m less than the length. The area is 28 m^2.

a) What are the dimensions of the rectangle?

b)What is the perimeter of the rectangle?

math1.docx Area of Rectangle = Length * Width

This implies that

X * (X-3) = 28

Expand the equation

X^2 - 3x = 28

X^2 - 3x - 28 = 0

Solving by factorization

X^2 - 7x + 4x -28 = 0

Factorize

X(X - 7) 4(X- 7) = 0

Combine

(X+4) (X-7) = 0

Therefore:

X=-4 or X=7

Since we cannot have a negative value for length ‘x’

X= 7

If the Length X= 7, then the Width = (7-3)=4

A) Dimension = 7m by 4m (Length by Width)

B)Perimeter = 2 (Length + Width)

Perimeter = 2 ( 7 + 4)

Perimeter = 2 (11)

Perimeter = 22

Check:

Length * Width = 28

7 * 4 = 28

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