Môn Toán Lớp 7: `21/5 + 3 : |x/4 + 2/3 | = 6` Cứu emm

2 bình luận về “Môn Toán Lớp 7: `21/5 + 3 : |x/4 + 2/3 | = 6` Cứu emm”

1. 21/5+3:|x/4+2/3|=6

   =>3:|x/4+2/3|=6-21/5

   =>3:|x/4+2/3|=9/5

   =>|x/4+2/3|=3:9/5

   =>|x/4+2/3|=5/3

   Trường hợp 1:

   x/4+2/3=5/3

   =>x/4=1

   =>x=4

   Trường hợp 2:

   x/4+2/3=-5/3

   =>x/4=(-5)/3-2/3

   =>x/4=(-7)/3

   =>x=(-7)/(3).4

   =>x=-28/3

   Vậy x in{4;-28/3}

    

   Trả lời
2. 21/5+3:|x/4+2/3|=6

   => 3:|x/4+2/3|=6-21/5

   => 3:|x/4+2/3|=9/5

   => |x/4+2/3|=3:9/5

   => |x/4+2/3|=5/3

   =>\(\left[ \begin{array}{l}\dfrac x4+\dfrac23=\dfrac53\\\dfrac x4+\dfrac23=-\dfrac53\end{array} \right.\) 

   =>\(\left[ \begin{array}{l}\dfrac x4=1\\\dfrac x4=-\dfrac73\end{array} \right.\) 

   =>\(\left[ \begin{array}{l}x=4\\x=-\dfrac{28}{3}\end{array} \right.\) 

   Vậy x in {4;-28/3}

   Trả lời