\(\frac1R=\frac1{2.3}+\frac1x \\~\\ \frac1R-\frac1{2.3}=\frac1x \\~\\ x(\frac1R-\frac1{2.3})=1 \\~\\ x=\frac{1}{(\frac1R-\frac1{2.3})} \\~\\ x=\frac{1}{(\frac{(2.3)1}{(2.3)R}-\frac{1(R)}{2.3(R)})} \\~\\ x=\frac{1}{(\frac{2.3-R}{2.3R})} \\~\\ x=\frac{2.3R}{2.3-R} \qquad\text{when }R\neq0\,.\)
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