Question

calcule
a) 3/7+7/49+8/7
b) 3/12+4/6+2/36+30/9
c) 7/9
d)1/20
f) 18/61
g)48/60

Answer 1

a)
= 3/7+7/49 (:7)/(:7) +8/7
= 3/7 + 1/7 + 8/7
= 12/7

b)
= 3/12 (:3)/(:3) +4/6 (:2)/(:2) +2/36 (:2)/(:2) +30/9
= 1/4 + 2/3 + 1/18 + 30/9
= (9.1 + 12.2 + 2.1 + 4.30)/36
= (9+24+2+120)/36
= (35+120)/36
= 155/36

MMC:
4,3,18,9: 2
2,3,9,9: 2
1,3,9,9: 3
1,1,3,3: 3
1,1,1,1 = 2.2.3.3 = 4.9 = 36

c) 7/9 (irredutível)

d)1/20 (irredutível)

f) 18/61 (irredutível)

g)48/60 (:12)/(:12) = 4/5