Đáp án:
Giải thích các bước giải:
a=$\frac{51}{23}$ +$\frac{7}{19}$ -$\frac{5}{23}$+ $\frac{12}{19}$+$\frac{1}{2}$
=$\frac{46}{23}$+$\frac{19}{19}$ +$\frac{1}{2}$
=2+1+$\frac{1}{2}$
=$\frac{7}{2}$
25.($\frac{-1}{5}$)³ -$\frac{1}{2}$
=25.$\frac{-1}{125}$ -$\frac{1}{2}$
=$\frac{-1}{5}$ -$\frac{1}{2}$
=$\frac{-7}{10}$
b2
a x:($\frac{-1}{3}$)³ =$\frac{-1}{3}$
=>x:$\frac{-1}{27}$=$\frac{-1}{3}$
=>27x=$\frac{1}{3}$
=>x=$\frac{1}{81}$
b (x+3)(x-5)<0
=>$\left \{ {{x-5<0} \atop {x+3<0}} \right.$
=>$\left \{ {{x<5} \atop {x<-3}} \right.$
c I x+$\frac{4}{5}$I-$\frac{1}{7}$=0
=>I x+$\frac{4}{5}$I =$\frac{1}{7}$
=> $\left \{ {{x+$\frac{4}{5}$=-$\frac{1}{7}$ } \atop {x+$\frac{4}{5}$=$\frac{1}{7}$ }} \right.$
=>$\left \{ {{x=-$\frac{33}{35}$ } \atop {x=$\frac{-23}{35}$ }} \right.$
Cho mik xin 5* nha bạn
