Solve for a
a=-\frac{1}{3}+\frac{1}{3r}
r\neq 0
Solve for r
r=\frac{1}{3a+1}
a\neq -\frac{1}{3}
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3ar=r\left(-1\right)+1
Multiply both sides of the equation by r.
3ra=1-r
The equation is in standard form.
\frac{3ra}{3r}=\frac{1-r}{3r}
Divide both sides by 3r.
a=\frac{1-r}{3r}
Dividing by 3r undoes the multiplication by 3r.
a=-\frac{1}{3}+\frac{1}{3r}
Divide -r+1 by 3r.
3ar=r\left(-1\right)+1
Variable r cannot be equal to 0 since division by zero is not defined. Multiply both sides of the equation by r.
3ar-r\left(-1\right)=1
Subtract r\left(-1\right) from both sides.
3ar+r=1
Multiply -1 and -1 to get 1.
\left(3a+1\right)r=1
Combine all terms containing r.
\frac{\left(3a+1\right)r}{3a+1}=\frac{1}{3a+1}
Divide both sides by 3a+1.
r=\frac{1}{3a+1}
Dividing by 3a+1 undoes the multiplication by 3a+1.
r=\frac{1}{3a+1}\text{, }r\neq 0
Variable r cannot be equal to 0.
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