25m4-0,5x40x5x0,2x20x0,25
1+2+8+...+129+156
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a)\(\frac{25.4-0,5\cdot40\cdot0,2\cdot20\cdot0,25}{1+2+8+...+129+156}\)
\(=\frac{100-100}{1+2+8+...+156}\)
\(=\frac{0}{1+2+8+...+156}\)
\(=0\)
b)\(\frac{0,5\cdot40-0,5\cdot20\cdot8\cdot0,1\cdot0,25\cdot10}{128:8.16.4\left(4+52:4\right)}=\frac{20-20}{128:8.16.4.\left(4+52:4\right)}=\frac{0}{128:8.16.4.\left(4+52:4\right)}=0\)
Bài 1:
a.
$-12-(-46)=-12+46=46-12=34$
b.
$-(-8)-54=8-54=-(54-8)=-46$
c.
$-15-(-72)=-15+72=72-15=57$
Bài 2:
a. $(156-812)-(156-12)=156-812-156+12$
$=(156-156)-(812-12)=0-800=-800$
b.
$-(-72+83)-(72+17)=72-83-72-17=(72-72)-(83+17)$
$=0-100=-100$
c.
$-(-23-78)+(77-178)=23+78+77-178$
$=(23+77)-(178-78)=100-100=0$
d.
$(-213-156)-(-213+44)=-213-156+213-44=(-213+213)-(156+44)$
$=0-200=-200$
5/6 + 7/12 = 10/12 + 7/12 = 17/12
9/16 - 3/8 = 9/16 - 6/16 = 3/16
11/10 + 3/5 : 2/3 =11/10 + 3/5 x 3/2 = 11/10 + 9/10 = 20/10 = 2
\(\dfrac{5}{6}+\dfrac{7}{12}=\dfrac{10}{12}+\dfrac{7}{12}=\dfrac{17}{12}\)
\(\dfrac{9}{16}-\dfrac{3}{8}=\dfrac{9}{16}-\dfrac{6}{16}=\dfrac{3}{16}\)
\(\dfrac{11}{10}+\dfrac{3}{5}:\dfrac{2}{3}=\dfrac{11}{10}+\dfrac{3}{5}\times\dfrac{3}{2}=\dfrac{11}{10}+\dfrac{9}{10}=\dfrac{20}{10}=2\)
=> (2+2x)[(2x-2)/2+1]/2=156
=>2(x+1)x/2=156
=>x(x+1)=156
=>x(x+1)=12.13
=>x=12
`136 -4^2 : x=134`
`=> 136-16:x=134`
`=> 16:x= 136-134`
`=> 16:x=2`
`=>x=16:2`
`=>x=8`
__
`19-5(x-1)=4`
`=> 5(x-1)=19-4`
`=> 5(x-1) =15`
`=> x-1=15:5`
`=>x-1=3`
`=>x=3+1`
`=>x=4`
__
`257-(x^2-1) =177`
`=>x^2-1=257-177`
`=>x^2-1=80`
`=>x^2=80+1`
`=>x^2=81`
`=>x^2=(+- 9)^2`
`=> x= +- 9`
__
`(x^2-17) : 8=2^3`
`=> x^2 -17 = 8 * 8`
`=> x^2 -17= 64`
`=> x^2 =64+17`
`=>x^2=81`
`=>x^2=(+- 9)^2`
`=> x= +- 9`
136 - 4² : x = 134
4² : x = 136 - 134
8 : x = 2
x = 8 : 2
x = 4
--------
129 - 5(x - 1) = 4
5(x - 1) = 129 - 4
5(x - 1) = 125
x - 1 = 125 : 5
x - 1 = 25
x = 25 + 1
x = 26
------------
257 - (x² - 1) = 177
x² - 1 = 257 - 177
x² - 1 = 80
x² = 80 + 1
x² = 81
x = -9 hoặc x = 9
--------
(x² - 17) : 8 = 8
x² - 17 = 8 . 8
x² - 17 = 64
x² = 64 + 17
x² = 81
x = -9 hoặc x = 9