Question

Sendo a= -1/5, b= 0,8 e c= -7/4, determine o valor de -a - b + c.

Answer 1

- a - b + c =

a = - 1/5
b = 0,8 = 8/10  = 4/5 
c = - 7/4 

- ( - 1/5) - ( + 4/5 ) + ( - 7/4 )
+ 1/5 - 4/5 - 7/4 = 
mmc = 20
( +4 - 16 - 35)/20  =  ( + 4 - 51)/20 = - 47/20 ***

Answer 2

Vamos lá

-a-b+c=?
    ↓

$-(\dfrac{-1}{5}) -(+0,8)+( \dfrac{-7}{4} ) \\ \\ \\ \dfrac{1}{5} -0,8- \dfrac{7}{4} \\ \\ \\ \dfrac{-3}{5} - \dfrac{7}{4} = \boxed{\dfrac{-47}{20}}$


Resposta --> -47/20