Question 85627
Isolate the variables:

54 - 22.5 = 2c + {{{5.7/c}}}
31.5 = 2c + {{{5.7/c}}}

Multiply everything by c:

31.5c = {{{2c^2}}} + c{{{5.7/c}}}
31.5c = {{{2c^2}}} + 5.7

Set = 0:

{{{2c^2}}} - 31.5c + 5.7 = 0

Multiply by 10 [to shift the decimal points]:

{{{20c^2}}} - 315c + 57 = 0

Apply the quadratic formula:

x = {{{(-b +- sqrt(b^2-4*a*c ))/(2*a) }}}
  = {{{(315 +- sqrt((-315)^2-4*20*57 ))/(2*20) }}}
  = {{{(315 +- sqrt(99,225-4560))/40}}}
  = {{{(315 +- sqrt(94,665))/40}}}