Question

Ecuaţie de forma ax^2+bx+c=0 , unde a,b,c aparţine R , a nu este egal cu 0 .

1)x^2-7x+6=0

2)4x^2-12x+5=0

3)x^2-5x+6=0

4)x^2-4√2x-6=0

5)x^2-2√5x+5=0

6)x^2-2√7x+7=0

7)x^2-4x+1=0

8)x^2-2x-1=9


Dau 40 de puncte!

Answer 1

Răspuns:

1.

delta=(-7)^2 - 4•1•6=25 =>rad.delta=5

x1=(7-5)/2=1

x2=(7+5)/2=6

2.

delta=(-12)^2 - 4•4•5=64 =>rad.delta=8

x1=(12-8)/8=1/2

x2=(12+8)/8=5/2

3.

delta=(-5)^2 - 4•1•6=1 =>rad.delta=1

x1=(5-1)/2=2

x2=(5+1)/2=3

4.

delta=(-4rad2)^2 - 4•1•(-6)=56 =>rad.delta=3rad6

x1=(4rad2-3rad6)/2

x2=(4rad2+3rad6)/2

5.

delta=(-2rad5)^2 - 4•1•5=0 =>x1=x2=2rad5/2=rad5

6.

delta=(-2rad7)^2 - 4•1•7=0 =>x1=x2=2rad7/2=rad7

7.

delta=(-4)^2 - 4•1•1=12 =>rad.delta=2rad3

x1=(4-2rad3)/2=2-rad3

x2=(4+2rad3)/2=2+rad3

8.

delta=(-2)^2 - 4•1•(-1)=8 =>rad.delta=2rad2

x1=(2-2rad2)/2=1-rad2

x2=(2+2rad2)/2=1+rad2