Question

15*15=X(X+16)
CUM IL DETERMIN PE X?
MULTUMESC

Answer 1

x(x+16)=15 * 15

x²+16x-15 *15 = 0

x²+16x-225=0

Putem forma un patrat perfect:

x²+16x+64-289=0

(x+8)²=289

|x+8|=17

Deducem doua cazuri posibile:

i)x+8=17 ⇒ x=9

ii) x+8=-17 ⇒ x=-25

S={9,-25}