Solve for y
y=40
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2y+1=81
Square both sides of the equation.
2y+1-1=81-1
Subtract 1 from both sides of the equation.
2y=81-1
Subtracting 1 from itself leaves 0.
2y=80
Subtract 1 from 81.
\frac{2y}{2}=\frac{80}{2}
Divide both sides by 2.
y=\frac{80}{2}
Dividing by 2 undoes the multiplication by 2.
y=40
Divide 80 by 2.
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