а/Ь=1,(3)
a/b=13-1/9
a/b=12/9
a/b=4/3
a=4/3·b
3a+7b/5a-2b=
3·4/3+7b/5·4/3-2b=
se simplifica 3 cu 3 si ramane 4b+7b/20/3b-2b=
11b/20/3b-6/3b= deoarece se amplifica cu 3
11b/4/3b=
se simplifica b cu b si ramane 11/4/3=
11÷4/3=
11/1·3/4=33/4
sper ca intelegi ca bara aceia inseamna "supra", iar acel punct inseamna operatia de inmultire
