Question 570107
{{{1/R}}}={{{1/R1+1/R2}}}.
 The total resistance is 12.3 ohms. Let 2x-1=R1.
{{{1/12.3}}}={{{1/(2x-1)+1/R2}}}.
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A. Express the second resistance R2 as a function of x.
{{{1/12.3}}}={{{1/(2x-1)+1/R2}}}
Lets simplify things here
Let a = R1 = (2x-1)
Let b = R2
Rewrite the equation to
{{{1/12.3}}}={{{1/a}}} + {{{1/b}}}.
Multiply thru by 12.3ab
12.3ab*{{{1/12.3}}}= 12.3ab*{{{1/a}}} + 12.3ab*{{{1/b}}}
cancel the denominators, results
ab = 12.3b + 12.3a
Get b in terms of a
ab - 12.3b = 12.3a
Factor out b on the left
b(a-12.3) = 12.3a
b = {{{(12.3a)/((a-12.3))}}}
Replace a with (2x-1), and b with R2
R2 = {{{(12.3(2x-1))/(((2x-1)-12.3))}}}
:
R2 = {{{(24.6x-12.3)/(2x-13.3)}}}; is R2 in terms of x
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B. Find R2 if x is : ohms. You didn't give any value for x, you can find what that is and substitute it for x in the above, to find R2