Răspunsuri

2014-11-08T21:02:18+02:00
Am sa te ajut doar la primul pentru ca celelalte sunt la fel...

(2x-1)^2 - (x-3)(x+3 )= 3x (x-1) + 2x
=4x^2 - x^2 - 9 = 3x^2 - 3x +2x
=3x^2 -9 = 3x^2 -x | - (3x^2)
-9 = 3x^2 - x - 3x^2 (se simplifica) si ramane
-x = -9 

Tine minte regulile de baza
(a-b)^2 = a^2 - 2ab + b^2
(a+b)^2 = a^2 + 2ab + b^2
(a-b)(a+b) = a^2 - b^2
a(b + c) = ab + ac 
Cel mai inteligent răspuns!
2014-11-08T21:20:26+02:00
2a)
4x²-4x+1-x²-3x+3x+9=3x²-3x+2x
3x²-4x+10=3x²-x
3x²-3x²-4x+x+10=0
-3x+10=0          (-1)
3x-10=0
3x=10
x=10/3
b)
(5x-2x-2)/5=(x-2)/2
(3x-2)/5=(x-2)/2
2(3x-2)=5(x-2)
6x-4=5x-10
6x-5x=4-10
x=-6
3)
7(x-5)>3(2x-3)
7x-35>6x-9
7x-6x>35-9
x>26
x∈(26, +α)
c) avem 2 situati pt.modul
Ix+2I={x+2 pt.x≥-2
          {-(x+2) pt x<-2
situatia I
1-(x+2)/6=(2x-1)/3-x
(6-x-2)/6=(2x-1-3x)/3
(4-x)/6=(-x-1)/3
3(4-x)=6(-x-1)
12-3x=-6x-6
-3x+6x=-12-6
3x=-18
x=18/3
x=-6
sittuatia a II
1-(-x-2)/6=(2x-1)/3-x
(6+x+2)/6=(2x-1-3x)/3
(8+x)/6=(-x-1)/3
3(8+x)=6(-x-1)
24+3x=-6x-6
3x+6x=-6-24
9x=-30
x=-30/9
1 5 1