The square root is also called quadratic square root, which is expressed as (-+root sign), and the square root that belongs to non-negative number is called arithmetic square root. Positive numbers have two real square roots in opposite directions, while negative numbers have no square roots. Next, I will share with you the square root formula commonly used in junior high school.

Complete square formula: (a+b) 2 = A2+2ab+B2 (a-b) 2 = A2-2ab+B2.

Square difference formula: (a+b) (a-b) = a 2-b 2.

Multiplication and factorization A2-B2 = (a+b) (a-b) A3+B3 = (a+b) (A2-AB+B2) A3-B3 = (A-B (A2+AB+B2))

Trigonometric inequality | A+B |≤| A |+B||||| A-B|≤| A |+B || A |≤ B < = > -b≤a≤b

|a-b|≥|a|-|b| -|a|≤a≤|a|

The solution of the unary quadratic equation -b+√(b2-4ac)/2a -b-√(b2-4ac)/2a