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x(x+3.7)= 18.3

On my assignment I've got a question that I'm stuck with.  I've got to find dimensions of a rectangle with the
information that is given:
Area: 18.3 cm;
Width: x
Length: x+3.7
 
so i came up with:
x(x+3.7)=18.3
x2+3.7x-18.3=0
 
Then when I'm trying to use the quadratic equation formula - I come up with answers, which do not work for me. HELP!

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Richard P. | Fairfax County Tutor for HS Math and ScienceFairfax County Tutor for HS Math and Sci...
4.9 4.9 (587 lesson ratings) (587)
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The quadratic formula will work for this problem.
 
We have a = 1
b = 3.7
c = - 18.3
 
We compute (-3.7 + sqrt(3.72 + 4 18.3) /2   =  2.81
 
We must take the positive sign of the square root, else we get a negative length (not physical).
Note also that the expression has + 4 18.3  because c is negative.
 
To check, we note that 2.81 (2.81 + 3.7) does equal 18.3