## tìm x a) (2/5-x)^3=-8/27 b)4/3:x=3/4:2/5 c) 1/2x:8/7=0,03:4/11

Question

tìm x
a) (2/5-x)^3=-8/27
b)4/3:x=3/4:2/5
c) 1/2x:8/7=0,03:4/11

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8 tháng 2020-10-16T05:54:38+00:00 2 Answers 89 views 0

1. Đáp án:

a)

 (2/5 -x)^3 = (-8/27) = (-2/3)^3

 => 2/5 – x = -2/3

 => x= 2/5 +2/3

 => x= 16/15

b)

 4/3 : x = 3/4 : 2/5

 4/3 : x =15/8

 x =4/3 : 15/8

 x  =32/45

c)

 1/(2) *x : 8/7 = 0,03 * 4/11

=> 1/(2) *x : 8/7 = 3/275

 1/(2) x = 24/1925

 x = 48/1925

2. Bạn tham khảo!
$a)$ $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $\dfrac{-8}{27}$
$→$ $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $($ $\dfrac{2}{3}$ $)$³ và $($ $\dfrac{2}{5}$ $-$ $x$ $)$³ $=$ $($ $\dfrac{-2}{3}$ $)$³
$→$ $\dfrac{2}{5}$ $-$ $x$ $=$ $\dfrac{2}{3}$ và $\dfrac{2}{5}$ $-$ $x$ $=$ $\dfrac{-2}{3}$
$→$ $x$ $=$ $\dfrac{2}{5}$ $-$ $\dfrac{2}{3}$ và $x$ $=$ $\dfrac{2}{5}$ $-$ $\dfrac{-2}{3}$
$→$ $x$ $=$ $\dfrac{-4}{15}$ và $x$ $=$ $\dfrac{16}{15}$
$b)$ $\dfrac{4}{3}$ $:$ $x$ $=$ $\dfrac{3}{4}$ $:$ $\dfrac{2}{5}$
$→$ $\dfrac{4}{3}$ $:$ $x$ $=$ $\dfrac{15}{8}$
$→$ $x$ $=$ $\dfrac{4}{3}$ $:$ $\dfrac{15}{8}$
$→$ $x$ $=$ $\dfrac{32}{45}$
$c)$ $\dfrac{1}{2}$ $.$ $x$ $:$ $\dfrac{8}{7}$ $=$ $0.03$ $:$ $\dfrac{4}{11}$
$→$ $\dfrac{1}{2}$ $.$ $x$ $:$ $\dfrac{8}{7}$ $=$ $\dfrac{3}{275}$
$→$ $\dfrac{1}{2}$ $.$ $x$ $=$ $\dfrac{3}{275}$ $.$ $\dfrac{8}{7}$
$→$ $\dfrac{1}{2}$ $.$ $x$ $=$ $\dfrac{24}{1925}$
$→$ $x$ $=$ $\dfrac{24}{1925}$ $:$ $\dfrac{1}{2}$
$→$ $x$ $=$ $\dfrac{12}{1925}$
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