Question

scrieti multimea solutilor ecuatiiei 2x+3=x+8, 2x+3=2(
x+1), 3(x+1)=3(x+2)-3,;;;rezolvati multimea numerelor naturale ecuatiile 2x+7=43+x;;;;84:(x-3)=12;;3(4+5x)=72

Answer 1

a)2x+3=x+8
2x-x=8-3
x=5=>x∈N
b)2x+3=2(x+1)
2x+3=2x+2
2x-2x=2-3
x=-1=>x∉N
c)3(x+1)=3(x+2)-3
3x+3=3x+6-3
3x-3x=6-3-3
x=0=>x∈N
d)2x+7=43+x
2x-x=43-7
x=36
e)84:(x-3)=12
x-3=84·12
x-3=1008
x=1008+3
x=1011
f)3(4+5x)=72
12+15x=72
15x=72-12
15x=60
x=$\frac{60}{15}$
x=4