Answer:
[tex]X_1=\frac{YX_2}{X_2-Y} \\\\[/tex]
Step-by-step explanation:
[tex]\frac{1}{Y}=\frac{1}{X_1}+\frac{1}{X_2}[/tex]
First subtract the 1/x2
[tex]\frac{1}{Y} - \frac{1}{X_2}=\frac{1}{X_1}[/tex]
Next subtract the fractions on the left
[tex]\frac{X_2-Y}{YX_2}=\frac{1}{X_1}\\[/tex]
Next Multiply by x1
[tex]\frac{(X_1)X_2-Y}{YX_2}=1\\[/tex]
Next divide both sides by the remaining parts (not x1)
[tex]X_1=\frac{YX_2}{X_2-Y} \\\\[/tex]
