Question

16/20+ (-15)/13 + 17/50

Answer 1

\(=\dfrac{16\times390}{20\times390}+\dfrac{-15\times600}{13\times7800}+\dfrac{17\times156}{50\times156}\\ =\dfrac{6240-9000+2652}{7800}=\dfrac{-108}{7800}=-\dfrac{9}{650}\)

Answer 2

20 = 2².5

13 = 13

50 = 2.5²

BCNN (20,13,50) = 2².13.5² = 1300

tìm thừa số phụ

1300 : 20 = 65

1300 : 13 = 100

1300 : 50 = 26

MSCNN = 1300

16/20 = 16/20 x 65/65 = 1040/1300

(-15)/13 = (-15)/13 x 100/100 = (-1300)/1300

17/50 = 17/50 x 26/26 = 442/1300

1040/1300 + (-1300)/1300 - 442/1300 = (-702)/1300 = (-9)/650