Question

Rezolvati in Q ecuatiile>
2x+1=x+x+1
7*1/2 + 2-4/5 : x=  10

Answer 1

2x+1 = x+x+1  ⇒  2x - 2x = 1 - 1  ⇒  0 = 0   (este o ecuatie ne definita ... adica: ecuatia are o infinitate de solutii ) ;
 
7 / 2 + 2 - 4 /5 x = 10 | *10x (... numitorul comun)
35x + 20x - 4 = 100x 
-100x+55x = 4
       -45x = 4
       x = - 4 / 45 ∈ Q