Question

rezilvati ecuatia ( x patrat -4) ( 9 - xpatrat ) = 0 , unde x aprtine lui Z

Answer 1

(x²-4)(9-x²)=0
(x-2)(x+2)(3-x)(3+x)=0
Egalam fiecare paranteza cu 0:
x-2=0 ⇒x=2
x+2=0⇒x=-2
3-x=0⇒x=3
3+x=0⇒x=-3
S:x∈{-2,2,-3,3}

Answer 2

(x^2-4)•(9-x^2)=0
Un produs da 0 cand macar unul din termeni este 0
x^2-4=0
x^2=4
x=+/-√4
x=+2 sau x=-2

9-x^2=0
9=x^2
x=+/-√9
x=3 sau x=-3
Deci x€{-3,-2,2,3}