Question

Am nevoie de ajutor la ex 5 și 6.

5.Rezorvati in R ecuatile :
6.Rezolvați in R ecuatile :

!!! DAU COROANA!!! ​

Answer 1

Răspuns:

5. a) $x^{2}$ -5x+6= 0      Δ = $b^{2}$-4ac= 25-4*6=1  

x1= (-b- $\sqrt{D }$)/2a= (5-1)/2= 4/2=2    x1=2

x2= (-b+$\sqrt{D}$)/2a= (5+1)/2= 6/2= 3    x2=3

b) $x^{2}$ +x- 6=0      Δ = 1+24= 25

x1= (-1-5)/2= -6/2= -3    x1= -3

x2=(-1+5)/2= 4/2= 2     x2=2

c) $x^{2}$- 7x+12= 0     Δ = 49-48=1

x1=(7-1)/2= 6/2= 3   x1=3

x2=(7+1)/2=8/2=4   x2= 4

d) $x^{2}$ +x-12= 0      Δ = 1+48=49

x1=(-1-7)/2=-8/2= -4     x2= (-1+7)/2= 6/2= 3

6. a)2$x^{2}$  +x-3= 0     Δ = 1 +4*3*2=25

x1=(-1-5)/4= -6/4= -3/2

x2=(-1+5)/4=4/4=1

b) 2$x^{2}$ -x -15=0     Δ = 1+15*2*4=121

x1=(1-11)/4= -10/4= -5/2

x2=(1+11)/4= 12/4=3

c) 3$x^{2}$ -5x+2= 0    Δ = 25- 2*3*4= 1

x1=(5-1)/6= 4/6= 2/3

x2=(5+1)/6= 6/6=1

d) 2$x^{2}$ -5x+2 =0   Δ = 25- 2*2*4=9

x1=(5-3)/4=2/4= 1/2

x2=(5+3)/4=8/4=2