a+b+c=495
a=2c, c=[tex] \frac{1}{2}a [/tex]
b=[tex] \frac{1}{4}a-9 [/tex]
[tex] a+ \frac{1}{4}a-9+ \frac{1}{2}a =495 [/tex]
aducem la acelasi numitor, amplificam a,9, 495 cu 4 si 1/2 a cu 2
[tex] \frac{4a}{4}+ \frac{1a}{4}- \frac{36}{4}+ \frac{2a}{4}= \frac{1980}{4} [/tex]
4a+2a-36+a=1980
7a=1980+36
7a=2016
a=2016:7
a=288
c=288:2
c=144
b=288:4-9
b=63
