daca x/y=2/3 atunci 5x + 7y / 9x-3y

Răspuns :

Ti-am lasat in atasament :
Vezi imaginea АНОНИМ
X/Y = 2/3 ==> X = 2Y/3

5X+7Y/ 9X-3Y =

= (10Y/3 + 7Y)/(18Y/3 - 3Y) =

= [(10Y+7×3Y)/3] /(6Y-3Y)=

= (10Y+21Y)/3 / 3Y =

= 31Y/9Y =

= 31/9