Question

Daca a;b;c apartine N si a;b;c direct proportionale cu 2, 3 respectiv 4, iar ab+bc=72. Aflati a,b,c

Answer 1

a, b, c dp cu 2, 3, 4 rezulta a/2= b/3=c/4=k ⇒a=2k b=3k c=4k
ab=bc=72⇒6k²+12k²=72⇒18k²=72⇒k²=2⇒k= 2 dupa care inlocuiesti pe k in relatiile de mai sus si obtii a= 2*2 b=2*3 c=2*4 cu placere :)

Answer 2

a/2=b/3=c/4=k    a=2k    b=3k  c=4k      2kx3k+3kx4k=72    18k=72  k=4