Question

afla numerele ,,a,, , ,,b,, ,,c,,, daca: a+b=c;  a-b=b ; b+c=20.

Answer 1

a-b=b
a=2b
a+b=c si inlocuim
2b+b=c
c=3b
b+c=20
b+3b=20
4b=20  b=5  a=10  c=15

Answer 2

a+b=c⇒2b+b=c⇒3b=c
a-b=b⇒a=2b
b+c=20⇒b+3b=20⇒4b=20

b=20:4
b=5

a=2 x 5
a=10

c=3 x 5
c=15