Question

Demonstrati identitatea:
a)a²+3a+2=(a+1)(a+2);
b)x²-x-6=(x-3)(x+2).

Answer 1

$a) a^{2}+3a+2= a^{2} +a+2a+2=a(a+1) +2(a+1)=(a+1)(a+2)$
$b) x^{2} -x-6= x^{2} -3x+2x-6=x(x-3)+2(x-3)=(x-3)(x+2)$

Answer 2

a)a^2+3a+2=a^2+2a+a+2(am inumultit fiecare termen cu fiecare din cele doua paranteza)         (^-inseamna la puterea)
a^2+3a+2=a^2+3a+2(A) 
b)x^2-x-6=x^2+2x-3x-6
x^2-x-6=x^2-x-6(A)