Question

Numerele rationale a,b,c sunt direct proportionale cu 3,7 si 8 iar 8a+7b+3c=485
a)Aflati a,b,c
b)Rezolva ecuatia ax+b=c

Answer 1

a)
a/3=b/7=c/8
b=7a/3
c=8a/3
8a+7b+3c=485
8a+7*7a/3+3*8a/3=485
8a+49a/3+24a/3=485
24a+49a+24a=1455
97a=1455
a=15
b=7*15/3=35
c=8*15/3=40

b)
ax+b=c
15x+35=40
15x=5
x=5/15
x=1/3