Square roots and common factors

Answer: x=9x=−9

1. Take both square roots of 81:x=±9.
2. Both 9 and −9 square to 81.
3. Therefore x=9 or x=−9.
4. Enter both roots, in either order.

Answer: x=9x=−9

1. Divide both sides by 4:x2=81.
2. Taking both square roots gives x=±9.
3. Therefore x=9 or x=−9.
4. Enter both roots, in either order.

Answer: x=9x=−9

1. Add 81 to both sides: x2=81.
2. Take both square roots, not only the positive one: x=±9.
3. Therefore x=9 or x=−9.
4. Enter both roots, in either order.