Question

Rezolvati in R (multimea numerelor reale) inecuatia :

2(x+1) < $\sqrt{5} (x+1)$

Answer 1

2(x+1) < √5(x+1)
2x+2 < √5x+√5
2x-√5x < √5-2
(2-√5)x < √5-2
x < (√5-2)/(2-√5)
x < (√5-2)(√5+2)/(2-√5)(2+√5)
x < [(√5)²-2²]/[2²-(√5)²]
x < (5-4)/(4-5)
x < 1/(-1)
x < -1
x apartine (-∞;-1)