Question

daca 2x=1 ,calculeaza
       ----  ---
       3y   2
a) x=....
   ---
   y
b)2x-y=....
  ---------
 x+y

Answer 1

a) 2x/3y= 1/2

2x=3y/2

x=3y/2/2

x=3y/2 * 1/2

x= 3y/4

x/y=  3y/4/y=  3y/4 * 1/y=  3/4

x/y=3/4

b) (2x-y)/(x+y)=  (2* 3y/4 -y) / (3y/4+y)=

=( 3y/2 -y) / (3y/4 +y)   aducem la acelasi numitor in paranteze=

= (3y-2y)/2 / (3y+4y)/4=

= y/2 /7y/4=

=y/2 * 4/7y= 2/7