Question

Determinati x si y stiind ca :
a). sunt invers proportionale cu 2 , 3 , iar x-y=10
b).sunt invers proportionale cu 3 , 4 , iar x-y=63

Answer 1

a) (a;b;) i.p.(2;3)
x-y=10
x/1/2=y/1/3=K }⇒x=K/2
                           y=K/3
K/2-K/3=10 (amplifici prima fractie cu3 si a doua cu 2)
3K/6-2K/6=1K/6
1K/6=10
1K=10x6
K=60
x=60:2=30
y=60:3=20
b) (x;y) i.p. (3;4)
x-y=63
x/1/3=y/1/4=K }⇒x=K/3
                          y=K/4
K/3-K/4=63 (amplifici prima fractie cu 4 si a doua cu 3)
4K/12-3K/12=63
1K/12=63
K=63x12
K=756
x=756:3=252
y=756:4=189