Solve for a
a=8
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\sqrt{10a+1}=9
Swap sides so that all variable terms are on the left hand side.
10a+1=81
Square both sides of the equation.
10a+1-1=81-1
Subtract 1 from both sides of the equation.
10a=81-1
Subtracting 1 from itself leaves 0.
10a=80
Subtract 1 from 81.
\frac{10a}{10}=\frac{80}{10}
Divide both sides by 10.
a=\frac{80}{10}
Dividing by 10 undoes the multiplication by 10.
a=8
Divide 80 by 10.
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