Question

daca x/y=2/5 , atunci: a) calculeaza 3x+2y/x+6y ; b)det x si y daca x-y=15​

Answer 1

Răspuns:

Explicație pas cu pas:

x/y=2/5  nptam x/y=t

a)(3x+2y)/(x+6y)=y(3x/y+2)/y(x/y+6)=(3t+2)/(t+6)=(3×2+2×5)/(1+6×5)=

=(6+10)/(1+30)=16/31

b)x=2y/5

x-y=15       2y/5-y=15        2y-5y=5×15     -3y=5×15      y=-25

x=-2×25/5=-10