(16,2:x) - 0,5 = 0,85

16,2 : x = 0,85 + 0,5

16,2 : x = 1,35

          x = 16,2 :1,35

          x = 12

\(\left(16,2:x\right)-0,5=0,85\)

\(\Leftrightarrow16,2:x=0,85-0,5\)

\(\Leftrightarrow16,2:x=0,35\)

\(\Leftrightarrow x=0,35\times16,2\)

\(\Leftrightarrow x=5,67\)

\(\left(16,2:x\right)-0,5=0,85\)

\(\Leftrightarrow16,2:x=0,85-0,5\)

\(\Leftrightarrow16,2:x=0,35\)

\(\Leftrightarrow x=0,35\times16,2\)

\(\Leftrightarrow x=5,67\)

K mik nka bn!:)

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Học tốt!:)

Lời giải:
$=16,2\times (5,7+3,7)-6,2\times (4,8+4,8)$

$=16,2\times 9,4-6,2\times 9,6$

$=16,2\times 9,4-6,2\times 9,4-6,2\times 0,2$

$=9,4\times (16,2-6,2)-6,2\times 0,2$

$=9,4\times 10-1,24$

$=94-1,24=92,76$

    3,25 : 0,125 + 3,25 : 0,5 + 3,25 : 0,25 + 3,25 : 0,5  + 3,25

= 3,25 x 8 + 3,25 x 2 + 3,25 x 4 + 3,25 x 2 + 3,25 x 1

= 3,25 x (8 + 2 + 4 + 2 + 1)

= 3,25 x (10 + 4 + 2 + 1)

= 3,25 x (14 + 2 + 1)

= 3,25 x (16 + 1)

= 3,25 x 17

= 55,25

3.(⅓x - ¼)² = ⅓ 

=> (\(\dfrac{1}{3x}\)- \(\dfrac{1}{4}\) )² = \(\dfrac{1}{9}\)

=>\(\left[{}\begin{matrix}\dfrac{1}{3x}-\dfrac{1}{4}=\dfrac{-1}{3}\\\dfrac{1}{3x}-\dfrac{1}{4}=\dfrac{1}{3}\end{matrix}\right.\)

=>\(\left[{}\begin{matrix}\dfrac{1}{3x}=\dfrac{-1}{12}\\\dfrac{1}{3x}=\dfrac{7}{12}\end{matrix}\right.\)        => \(\left[{}\begin{matrix}x=-4\\x=\dfrac{12}{21}=\dfrac{4}{7}\end{matrix}\right.\)

Vậy, tập nghiệm x thỏa mãn là S=\(\left\{-4;\dfrac{4}{7}\right\}\)

a)1.25*800*6.7=6700

b)4.5*2.5*40*80=36000

c)7.89*0.5*200=789

d)2.5*5.5*2*4110

k minh nhe ban chuc ban hoc gioi

thank very much

a, Kết quả là 6700

b, Kết quả là 36000

c, Kết quả là 789

d, Kết quả là 110

\(\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\left(0,5-1\dfrac{3}{5}\right)\)

\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\left(\dfrac{1}{2}-\dfrac{8}{5}\right)\)

\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{-3}{8}\times\dfrac{11}{10}\)

\(\Rightarrow\left(x:2,2\right)\times\dfrac{1}{6}=\dfrac{33}{80}\)

\(\Rightarrow x:2,2=\dfrac{33}{80}:\dfrac{1}{6}\)

\(\Rightarrow x:2,2=\dfrac{99}{40}\)

\(\Rightarrow x=\dfrac{99}{40}\times2,2\)

\(\Rightarrow x=\dfrac{1089}{200}\)

=>(x:2,2)*1/6=-3/8(1/2-8/5)=33/80

=>x:2,2=99/40

=>x=1089/200

a) \(\left(2,4-3x\right).0,5=0,9\)

\(2,4-3x=0,9:0,5\)

\(2,4-3x=1,8\)

\(3x=2,4-1,8\)

\(3x=0,6\)

\(x=0,6:3\)

\(x=0,2\)

b) \(\left(8,8x-50\right):0,4=51\)

\(8,8x-50=51.0,4\)

\(8,8x-50=20,4\)

\(8,8x=20,4+50\)

\(8,8x=70,4\)

\(x=70,4:8,8\)

\(x=8\)

c) \(\left(0,472-x\right):2=1,634\)

\(0,472-x=1,634.2\)

\(0,472-x=3,268\)

\(x=0,472-3,268\)

\(x=-2,796\)

d) \(1,6-\left(x-0,2\right)=6,5\)

\(x-0,2=1,6-6,5\)

\(x-0,2=-4,9\)

\(x=-4,9+0,2\)

\(x=-4.7\)

\(a.2,4-3x=1,8\)

\(3x=0,6\)

\(x=0,2\)

\(b.8,8x-50=20,4\)

\(8,8x=70,4\)

\(x=8\)

\(c.0,472-x=3,268\)

\(x=-2,796\)

\(d.x-0,2=-4,9\)

\(x=-4,7\)