Question

alguem me pode ajudar a resolver este sistema

Answer 1

${2(a-b)= - \frac{1}{2} ==>a-b=- \frac{1}{2}:2=- \frac{1}{2}* \frac{1}{2}=- \frac{1}{4}$
Logo: 
a-b= -1/4 --> b = a -(-1/4) --> b=a+1/4   (i)

$\frac{a}{2}- \frac{b}{4}= \frac{a}{8}$---mmc(2,4,8)=8
4a - 2b = a -->. -2b=a-4a --> -2b= -3a --> b= 3a/2  (ii)

(i) = (ii)
a + 1/4 = 3a/2 ---mmc(2,4) = 4
4a + 1 = 6a --> 2a = 1 -----> a = 1/2

(i) b = a + 1/4 
    b = 1/2 + 1/4 ---> b = 3/4

Resposta:
                    {a=1/2
                    {b=3/4