Răspuns:
Explicație pas cu pas:
a)
1/5 + 3 - 2 1/5 = x/5 + x/2
1/5 + 15/5 - 11/5 = 2x/10 + 5x/10
5/5 = 7x/10
1 = 7x/10
7x = 10
x = 10/7
b)
2,1(6) = (216 - 21)/90 = 195/90 = 39/18 = 13/6
2,(6) = (26 - 2)/9 = 24/9 = 8/3
8x/3 + 13/6 = x + 1
8x/3 - x = 1 - 13/6
8x/3 - 3x/3 = 6/6 - 13/6
5x/3 = -7/6
x = -3*7/5*6 = -7/10 = -0,7