Question

știind ca a+b=25,a-b=5. a=?,b=?

Answer 1

1) 25-5=20(bx2)
2) 20:2=10(b)
3) 25-10=15(a)
V:15-10=5

R: 10 ; 15

Answer 2

a+b=25
a-b=5 ⇒ a=5+b
5+b+b=25 ⇒ 5+2b=25 ⇒2b=25-5⇒2b=20⇒b=20:2
b=10
a+b=25
a+10=25
a=25-10
a=15