tính một cách hợp lí: B=-5/7+8/11+(-2/7)+1/2+(3/11+8/11)
2 câu trả lời
Đáp án + Giải thích các bước giải:
`B=-5/7+8/11+(-2/7)+1/2+(3/11+8/11)`
`B=-5/7+8/11-2/7+1/2+1`
`B=(-5/7-2/7)+1+(8/11+1/2)`
`B=(-5/7-2/7)+1+(16/22+11/22)`
`B=(-1)+1+27/22`
`B=0+27/22`
`B=27/22`
Vậy `B=27/22`
$\text{B = $\dfrac{-5}{7}$ + $\dfrac{8}{11}$ + $\dfrac{-2}{7}$ + $\dfrac{1}{2}$ + ( $\dfrac{3}{11}$ + $\dfrac{8}{11}$}$
$\text{B = ( $\dfrac{-5}{7}$ + $\dfrac{-2}{7}$ ) + $\dfrac{8}{11}$ + $\dfrac{1}{2}$ + ( $\dfrac{3}{11}$ + $\dfrac{8}{11}$ )}$
$\text{B = $\dfrac{-7}{7}$ + $\dfrac{8}{11}$ + $\dfrac{1}{2}$ + $\dfrac{11}{11}$}$
$\text{B = ( -1 ) + $\dfrac{8}{11}$ + $\dfrac{1}{2}$ + 1}$
$\text{B = [ ( -1 ) + 1 ] + $\dfrac{8}{11}$ + $\dfrac{1}{2}$}$
$\text{B = 0 + $\dfrac{8}{11}$ + $\dfrac{1}{2}$}$
$\text{B = $\dfrac{16}{22}$ + $\dfrac{11}{22}$}$
$\text{B = $\dfrac{16 + 11}{22}$}$
$\text{B = $\dfrac{27}{22}$}$
Vậy $\text{B = $\dfrac{27}{22}$}$