Question

Rezolvati ecuatiile si precizati daca solutile apartin multimii N sau Q+:
a) x+0.5=2.8
b) x- 3/4=5/2
c) 5 1/3-x=4
d) 0.(6):x=3
e) x:1.6=2 1/2
f) 0.1(3)*x=1/3
g) 3/2x+1/2=5/3
h) 2 1/2x-1/4=6
i) 0.4-0.2x=0.1
Va rogg mulltt ajutati-ma!!

Answer 1

a) x+0.5=2.8 
x=2.8-0.5
x=2,3=23/10
x∈Q+

b) x- 3/4=5/2
x=5/2+3/4
x=(10+3)/4
x=13/4
x∈Q+

c) 5 1/3-x=4
16/3-x=4
16-3x=12
3x=16-12
3x=4
x=4/3
x∈Q+

d) 0.(6):x=3
6/9:x=3
6/9x=3
27x=6
x=6/27=2/9
x∈Q+

e) x:1.6=2 1/2
x:1,6=5/2
x:16/10=5/2
x=5/2x16/10
x=4
x∈N

f) 0.1(3)*x=1/3
(13-1)/90*x=1/3
12/90*x=1/3
2x/15=1/3
6x=15
x=15/6=5/2
x∈Q+

g) 3/2x+1/2=5/3
n.c.=6x
3x3+3x=2x*5
9+3x=10x
10x-3x=9
7x=9
x=9/7
x∈Q+

h) 2 1/2x-1/4=6
5/2x-1/4=6
n.c.=4x
2x5-x=6*4x
10-x=24x
24x+x=10
25x=10
x=25/10
x=5/2
x∈Q+

i) 0.4-0.2x=0.1
0,2x=0,4-0,1
0,2x=0,3
x=0,3/0,2=3/2
x∈Q+