122=A2-92

Rewrite the equation as A2-92=122.

A2-92=122

Raise 9 to the power of 2.

A2-1⋅81=122

Multiply -1 by 81.

A2-81=122

A2-81=122

Raise 12 to the power of 2.

A2-81=144

Add 81 to both sides of the equation.

A2=144+81

Add 144 and 81.

A2=225

A2=225

Take the square root of both sides of the equation to eliminate the exponent on the left side.

A=±225

Simplify the right side of the equation.

Rewrite 225 as 152.

A=±152

Pull terms out from under the radical, assuming positive real numbers.

A=±15

A=±15

The complete solution is the result of both the positive and negative portions of the solution.

First, use the positive value of the ± to find the first solution.

A=15

Next, use the negative value of the ± to find the second solution.

A=-15

The complete solution is the result of both the positive and negative portions of the solution.

A=15,-15

A=15,-15

A=15,-15

Solve for A 12^2=A^2-9^2