tim x
a)x=1/5+2/11
b)x=1/13+-13/26
c)x=1/12+3/4 +-2/9
d) x/5=5/6+-19/30
tim x a)x=1/5+2/11 b)x=1/13+-13/26 c)x=1/12+3/4 +-2/9 d) x/5=5/6+-19/30
By aihong
By aihong
tim x
a)x=1/5+2/11
b)x=1/13+-13/26
c)x=1/12+3/4 +-2/9
d) x/5=5/6+-19/30
a) x = 1/5 + 2/11
x = 11/55 + 10/55
x = (11 + 10) / 55
x = 21/55
Vậy x = 21/55
b) x = 1/13 + (-13/26)
x = 1/13 – 13/26
x = 2/26 – 13/26
x = (2 – 13) / 26
x = -11/26
c) x = 1/12 + 3/4 + (-2/9)
x = 1/12 + 3/4 – 2/9
x = (1/12 + 3/4) – 2/9
x = (1/12 + 9/12) – 2/9
x = [(1 + 9) / 12] – 2/9
x = 10/12 – 2/9
x = 5/6 – 2/9
x = 11/18
Vậy x = 11/18
d) x/5 = 5/6 + (-19/30)
x/5 = 5/6 – 19/30
x/5 = 25/30 – 19/30
x/5 = 6/30
x/5 = 1/5
x = 1
Vậy x = 1
Đáp án:
Giải thích các bước giải:
a) x=$\frac{1}{5}$ +$\frac{2}{11}
⇔x=$\frac{11}{55}+ $\frac{10}{55}
⇒x=$\frac{21}{55}
b) x=$\frac{1}{13}-$\frac{13}{26}
⇔x=$\frac{2}{26}-$\frac{13}{26}
⇒x=$\frac{-11}{26}
c) x=$\frac{1}{12}+$\frac{3}{4}-$\frac{2}{9}
⇔ x=$\frac{1}{12}+$\frac{9}{12}-$\frac{2}{9}
⇔ x= $\frac{5}{6}-$\frac{2}{9}
⇒ x=$\frac{11}{18}
d) $\frac{x}{5}=$\frac{5}{6}-$\frac{19}{30}
⇔ $\frac{x}{5}= $\frac{25}{30}-$\frac{19}{30}
⇔$\frac{x}{5}=$\frac{1}{5}
⇔5x=5
=> x=1