Question

1) Rezolvati in Q ecuatia 5(x-1)=10-x
2) Calculati media artimetica a nr.
a) 3pe 9 si 5 pe 3
b)0,4 si 0, 75

Answer 1

5(x-1)=10-x
5x-5=10-x
5x+x=10+5
6x=15
x=15/6



ma=(3/9+5/3):2=18/9:2=2:2=1

ma=(0,4+0,75):2=1,15:2=0,575

Answer 2

1) 5( x - 1) = 10 - x
   5x - 5 = 10 - x
   5x + x = 10 + 5
   6x = 15
   x = 15 /6 ⇒ x = 5 /2 ∈ Q

2) ma = ( a + b) / 2      / = supra
   a) a = 3/ 9 ⇒ a = 1/ 3 si b = 5 /3
   ma = ( 1/ 3 + 5 /3 ) / 2 = ( 6/ 3) / 2 = 2 /2 = 1
   ma = 1
  b) a = 0,4 si b = 0, 75
     ma = ( 0,4 + 0,75) / 2 = 1,15/2 = 115/ 100 : 2 = 115/ 100 · 1/2 = 115/ 200
     ma = 0,575