Question

1). Rezolvaţi ecuaţiile:

a). x + 1 = 3x - 7
b). -2 - x = 3 - (2 - x)

17). Calculaţi:

a). (a/3 - 1)^2 + (a - 2/3)^2 + (a/2 - 1)(a/2 + 1) + (3a/2 - 2)^2

Ofer coroană!

Answer 1

1.
a)-2x=-8 =>x=4
b)-2-x=3-2+x
   -2-x=1+x
   -2-1=x+x
   -3=2x =>x=-3/2

17.
a)a²/9 - 2a/3 + 1 + a² - 4a/3 +4/9 + a²/4 - 1 + 9a²/4 - 6a + 4 =
(4a²-24a+36+36a²-48a+16+9a²-36+81a²-216a+144)/36=
(130a²-288a+160)/36=
2(65a²-144a+80)/36=
(65a²-144a+80)/18 - daca e scris corect...

Answer 2

a) x + 1 = 3x - 7
    x - 3x = - 1 - 7
    - 2x = - 8
    x = 8/2
    x = 4
b) - 2 - x = 3 - (2 - x)
    - x = 2 + 3 - 2 + 2x
    - x - 2x = 3
    - 3x = 3
     x = - 3 : 3  
     x = - 1
a) (a/3 - 1)² + (a - 2/3)² + (a/2 - 1)(a/2 + 1) + (3a/2 - 2)² = 
     a²/9 - 2a/3 + 1 + a² - 4a/3 + 4/9 + a²/4 - 1 + 9a²/4 - 12a/2 + 4 =
    (4a² - 24a + 36 + 36a² - 48a + 16 + 9a² - 36 + 81a² - 216a + 144)/36 = 
    (130a² - 288a + 160)/36 =           | : 2
    ( 65a² - 144a + 80)/18