Question 446907
The length of a rectangle flower garden is three feet more than its width. The area is 70 square feet. Using an algbriac equation find the length and the width of the flower garden. 
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Let x = width
then because "length of a rectangle flower garden is three feet more than its width" we get
x+3 = length
(basically, what you had)
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Now, you have to apply your knowledge of the area of any rectangle:
area = width * length
giving you your equation:
70 = x(x+3)
now we solve for x:
70 = x(x+3)
70 = x^2+3x
0 = x^2+3x-70
0 = (x+10)(x-7)
x = {-10, 7}
we can throw out the negative solution (extraneous) since it doesn't make sense leaving:
x = 7 feet (width)
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Length:
x+3 = 7+3 = 10 feet