Question

Multimea solutiilor reale ale ecuatiei (x-2)totul la puterea a doua =9

Answer 1

(x-2)²=9⇒x²-4x+4=9⇒x²-4x-5=0;
Δ=b²-4ac=16+20=36
x1=(4+6)/2=5
x2=(4-6)/2=-1
S∈{-1,5}