Question

determine o valor das somas algébricas a) -5/4+1/3 b) -1/2+3/4-2/5

Answer 1

a)
$-\frac{5}{4}+\frac{1}{3}=\frac{-15+4}{12}=-\frac{11}{12}$

b)
$-\frac{1}{2}+\frac{3}{4}-\frac{2}{5}=\frac{-10+15-8}{20}=\frac{-3}{20}$

Answer 2

-5/4 + 1/3

MMC  de 4, 3 = 12

(-5 . 3 + 1 . 4 ) / 12
(-15 + 4 ) / 12
=>  -11 / 12

===

-1/2 + 3/4 - 2/5

MMC de 2, 4, 5 = 20

(-1 . 10 + 3 . 5 - 2 . 4)  / 20
(-10 + 15 - 8) / 20
=>  -3 / 20