Question

fie proportia x/2=y/7. Determinati valoarea urmatoarelor rapoarte:
a) 21x/2y
b) 9x-y totul supra x+2y
c) 3x+y totul supra 7x-y
d) 6x+4y totul supra x

Answer 1

x/2=y/7 este echivalenta cu x/y=2/7
a)21/2 · 2/7 = 3

x/y=2/7 =>x=2y/7
b)$\frac{9* \frac{2y}{7} -y}{ \frac{2y}{7}+ 2y} = \frac{18y-7y}{2y+14y} = \frac{11y}{16y}= \frac{11}{16}$

c)$\frac{3* \frac{2y}{7}+y }{7* \frac{2y}{7}- y} = \frac{6y+7y}{14y-7y} = \frac{13y}{7y} = \frac{13}{7}$

d)$\frac{6* \frac{2y}{7}+4y }{ \frac{2y}{7} } = \frac{12y+28y}{2y} = \frac{40y}{2y} =20$