Question

afla numerele a si b, daca:a+b=50,iar a-b=10.

Answer 1

a + b = 50 
a - b = 10 
a = 10 + b 

10 + b + b = 50 
10 + 2b = 50 
2b = 50 - 10 
2b = 40 
b = 40 : 2
b = 20 
a = 10 + 20 = 30 

30 + 20 = 50
30 - 20 = 10 

Answer 2

a+b=50
a-b=10
a=10+b
10+b+b=50
2b=50-10
2b=40
b=20
a=20+10=30