Question

Calculaţi a, b şi c pentru :
a+b=105
c+b=120
a+b+2c=180

Answer 1

a+b+2c=180
105+2c=180
2c=180-105
2c=75
c=75 impartit la 2
c=37,5 

c+b=120
37,5+b=120
b=120-37,5
b=82,5

a+b=105
a+82,5=105
a=105-82,5
a=22,5

Answer 2

a+b+2c=180
150+2c=180/-150
2c=30/:2
c=15
c+b=120
15+b=120/-15
b=105
a+b=105
a+105=105/-105
a=0