Question

Aflaţi x ∈ N astfel încât:

a)3(2x-1)=141
b)8x+10=6x+18
c)29-5(x+1)=4
d)2(3x-1)=3(x+2)+4
e)[37-(x-1)×3]×2=14
f)[(x-3)×2+7]÷5=15.

Answer 1

a)3(2x-1)=141
2x-1=141:3
2x-1=47
2x=48
x=24
b)8x+10=6x+18
2x=8
x=4
c)29-5(x+1)=4
5(x+1)=29-4
5(x+1)=25
x+1=5
x=4
d)2(3x-1)=3(x+2)+4
6x-2=3x+6+4
3x=12
x=4
e)[37-(x-1)×3]×2=14
37-(x-1)×3=7
30=(x-1)×3
x-1=30:3
x-1=10
x=11

f)[(x-3)×2+7]÷5=15
(x-3)×2+7=75
(x-3)×2=75-7
(x-3)×2=68
x-3=34
x=37