Question

a expressão algebrica 3a-b/1-a , para a = -1 e b = 1/2 , tem valor numerico igual a : a=-1/2 b=1/4 c=3/2 d= -1/4 e= -7/4

Answer 1

$\boxed{\frac{3a-b}{1-a} =\frac{3.(-1) - \frac{1}{2}}{1-(-1)} =\frac{-3-\frac{1}{2}} {1+1}= \frac{ \frac{-6+1}{2}}{2} = - \frac{7}{2} . \frac{1}{2}= - \frac{7}{4}}$