Question

1. Rezolvati in multimea numerelor rationale ecuatia 3 pe 5 - 0,8x = 1 intreg 4 pe 5.\
2. Rezolvati in q ecuatia 3[0,2(7)x- 0,4] = 1,(3)x.

Answer 1

1.
3/5 - 0,8x = 1 4/5
 - 8x/10 = 9/5-3/5
 - 4x/5 = 6/5
4x=-6
x=-6/4
x=-3/2


2.
3[0,2(7)x- 0,4] = 1,(3)x
0,2(7)=(27-2)/90=25/90=5/18
1,(3)=(13-1)/9=12/9=4/3
4/10=2/5
3(5x/18- 2/5) = 4x/3
5x/18- 2/5 = 4x/9
5x/18- 4x/9=2/5
(5x-8x)/18=2/5
-3x/18=2/5
-x/6=2/5
x/6=-2/5
x=-12/5