**Equations Formulas**

Real numbers: a, b, c, p, q, u, v

Solutions: x_{1}, x_{2}, y_{1}, y_{2}, y_{3}

1. Linear equation in One Variable

Ax + b = 0 , x = –.

2. Quadratic Equation

ax^{2} + b x + c = 0 , x_{1,2} =

3. Discriminate

D = b^{2} -4ac

4. Viete’s Formulas

If x^{2} + px +q = 0 , than

5. ax^{2} +bx = 0 ,x_{1} = 0 , x_{2} = .

6. ax^{2 }+ c = 0, x_{1,2 } = ±

7. Cubic Equation. Cardano’s Formula.

y^{3} + py +q = 0,

y_{1 = } u +v, y_{2,3 = }

where

, v = .