• square it

• divide it by 2 and square the result

• divide it by 2 and take the square root of the result

• divide it by 2 only

• complete square by adding 4 to both sides

• take the square root of both sides

• subtract two on both sides

• Set the equation equal to zero

• Divide 10 by 2 and add the result to both sides

• Add a² and 10a together

• Subtract the 21 on both sides

• 2

• 4

• -2

• 1

• 64

• 25

• 81

• 9

• 144

Mathematical Equivalence

ON