Question

Cine ma poate ajuta cu o problema ?
Afla : 3a-4b+5c=?
a-b=40
a:b=3
b:2=c

Answer 1

a:b=3=>a=3b
a-b=40
3b-b=40
2b=40
b=40:2=20
c=b:2=20:2=10
a=3b=3•20=60
3a-4b+5c=3•60-4•20+5•10=180-80+50
=150