FORMULE DE CALCUL PRESCURTAT

1. \({{\left( a+b \right)}^{2}}={{a}^{2}}+2ab+{{b}^{2}};\)

2. \({{\left( a-b \right)}^{2}}={{a}^{2}}-2ab+{{b}^{2}};\)

3.  \((a-b)(a+b)={{a}^{2}}-{{b}^{2}};\)

4. \({{\left( a+b+c \right)}^{2}}={{a}^{2}}+{{b}^{2}}+{{c}^{2}}+2ab+2bc+2ca\)

5. \({{\left( a+b \right)}^{3}}={{a}^{3}}+3{{a}^{2}}b+3a{{b}^{2}}+{{b}^{3}}\);

6. \({{\left( a-b \right)}^{3}}={{a}^{3}}-3{{a}^{2}}b+3a{{b}^{2}}-{{b}^{3}}\);

7. \({{a}^{3}}-{{b}^{3}}=(a-b)({{a}^{2}}+ab+{{b}^{2}})\);

8. \({{a}^{3}}+{{b}^{3}}=(a+b)({{a}^{2}}-ab+{{b}^{2}})\).