Question

ajutor vreu si eu formulele de calcul prescurtat

Answer 1

(a+b)²=a²+2ab+b²
(a-b)²=a²-2ab+b²
a²-b²=(a-b)(a+b)
(a+b+c)=a²+b²+c²+2ab+2bc+2ac
(a-b+c)=a²+b²+c²-2ab+2ac-2bc

Answer 2

$(a+b)^2=a^2+2ab+b^2 \\ \\ (a+b)(a-b)=a^2-b^2 \\ \\ (a+b+c)^2=a^2+b^2+2ab+2bc+ac \\ \\ a^3+b^3=a+b^3 +3ab(a+b) \\ \\ a^3-b^3=(a-b)^3+3ab(a-b) \\ \\ (a+b)^3=a^3+b^3+3a^2b+3ab^2=a^3+b^3+3ab(a-b)$

$\text{Principalele formule}$