Question

Ma puteti ajuta va rog frumos la o problema?
Determinati numerele naturale a,b,c stiind ca:
a)a+b=90,b+c=21,a+c=75
b)a+b=70,b+c=11,a+c=65

Answer 1

a+b=90
b+c=21
a+c=75
2a+2b+2c=186
2a+2b=180
2c=186-180
2c=6
c=6:2
c=3
b+3=21
b=21-3
b=18
a+18=90
a=90-18
a=72
a+b=72+18=90
b+c=18+3=21
a+c=72+3=75

a+b=70
b+c=11
a+c=65
2a+2b+2c=146
2a+2b=140
2c=146-140
2c=6
c=6:2
c=3
b+3=11
b=11-3
b=8
a+b=70
a+8=70
a=70-8
a=62
a+b=62+8=70
b+c=8+3=11
a+c=62+3=65