Răspunsuri

2014-04-26T13:46:54+03:00

Punctul A:

4a=5b=7c

b=(4a)/5

x*b=a⇒x*[(4a)/5]=a⇒(4ax)/5=a⇒5a=4ax⇒x=5/4⇒x=1,25⇒x=125%

Punctul B

3a+c=285⇒3a+(4a)/7=285⇒aducem la acelasi numitor⇒21a+4a=1995⇒25a=1995⇒a=79,8

b=(4a)/5=(4*79,8)/5=319,2/5=63,84

c=(4a)/7=(4*79,8)/7=319,2/7=45,6