Solve: negative 1 over 2 x + 3 = –x + 7

 1/(2x+3) = -x +7 
cross-multiply 
1 = (2x+3)(-x+7) 
1 = -2x^2 +14x -3x +21 
2x^2 -11x -20 = 0 
use quadratic formula 
x = {11 +/- sqrt(281)} /4 

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or do you mean
1/2x + 3 = -x + 7 
multiply all terms by x 
1/2 + 3x = -x^2 + 7x 
x^2 -4x = -1/2 
x^2 -4x + 4 = 4 - 1/2 
(x-2)^2 = 14/4 
x-2 = +/-sqrt(14)/2 
x = [4 +/- sqrt14] /2

hope this helps!

There is no association.