Question

ma ajutati
Rezolvati in R inecatia: b)-x²-2x+48<0; c)8x²+10x-3<0; d) 25x²-10x+1>0;

Answer 1

b)Se calculeaza radacinile ecuatiei: Δ=196⇒√Δ=14⇒x1=-8, x2=6

Trasam tabelul semnelor

x -∞ -8 6 +∞

.................................................................................................

f(x) - - - 0 +++ 0 - - -

⇒x∈(-∞;-8)∪(6;+∞)

c) Dupa rezolvarea ecuatiei, obtinem radacinile x1=1/4 si x2=-3/2⇒x∈(-3/2;1/4)

d)x1=x2=1/5⇒ecuatia are doua solutii reale egale

In acest caz tabelul semnelor este:

x -∞ 1/5 +∞

.................................................................................................

f(x) + + + + 0 + + + +

⇒x∈(-∞;1/5)∪(1/5;+∞)