Income tax is a direct tax which is levied on the income of private individuals. Various income tax systems exist. Those range from a flat tax to an extensive progressive tax[?] system.
Taxes levied on the income of companies is called corporate tax[?].
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Derivation
The quadratic formula is derived by the method of completing the square[?].
<math>ax^2+bx+c=0</math>
Dividing our quadratic ...