Đáp án:
a/ $\dfrac{203}{24}$
b/ $\dfrac{8215}{18}$
Giải thích các bước giải:
a/
`(136/15-28/5+62/10)* 21/24`
`=(272/30-168/30+186/30)*21/24`
`=((272-168+186)/30)* 21/24`
`=290/30*21/24`
`=29/3*7/8`
`=203/24`
b/
`5/6+6 5/6*(1*1 5/20-9 1/4)*8 1/3`
`=5/6+41/6*(1* 25/20-37/4)*25/3`
`=5/6+41/6*(1*5/4-37/4)*25/3`
`=5/6+41/6*(5/4-37/4)*25/3`
`=5/6+41/6*(20/16-148/16)*25/3`
`=5/6+41/6*(-128)/16*25/3`
`=5/6+41/6*-8*25/3`
`=5/6+(41/6*-8)*25/3`
`=5/6+(-164)/3*25/3`
`=5/6+ (-4100)/9`
`=24645/54=8215/18`