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(1+2+3+4+9+22+88)x(99-77+8-30)
=[(1+9)+(88+22)+(2+3+4)]x[(99-77)+(8-30)]
=(10+110+9)x[22+(-22)]
=129x0
=0
tick cho mk nha bạn
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a, \(\frac{2}{3}\)x \(\frac{10}{21}\)x \(\frac{3}{2}\)= \(\frac{2x10x3}{3x21x2}\) = \(\frac{10}{21}\)
b, \(\frac{22}{5}\)x \(12\)x\(\frac{5}{22}\) = \(\frac{22x12x5}{5x22}\) = \(12\)
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( x + 1 ) + ( x + 3 ) + ( x + 5 ) + ... + ( x + 15 ) = 88
=> x + 1 + x + 3 + x + 5 + ... + x + 15 = 88
=> x . ( 1 + 3 + 5 + ... + 15 ) = 88
=> x . 64 = 88
=> x = 88 : 64
=> x = 1,375
Dãy trên có số số x là :
( 15 - 5 ) : 2 + 1 = 8 (số )
x . 8 + ( 1 + 3 + ... + 15 ) = 88
Tổng của dãy 1 + 3 + .. + 15 là :
( 15 + 1 ) x 8 : 2 = 64
x . 6 + 64 = 88
x . 6 = 88 - 64
x . 6 = 24
x = 24 : 6
x = 4
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a, \(\dfrac{5\times11\times15\times18}{6\times15\times22\times10}\)
= \(\dfrac{5\times11\times15\times6\times3}{6\times15\times11\times2\times2\times5}\)
= \(\dfrac{5\times11\times15\times6}{5\times11\times15\times6}\) \(\times\) \(\dfrac{3}{2\times2}\)
= 1 \(\times\) \(\dfrac{3}{4}\)
= \(\dfrac{3}{4}\)
b, \(\dfrac{7}{12}\) \(\times\) \(\dfrac{3}{5}\) + \(\dfrac{3}{5}\) \(\times\) \(\dfrac{5}{12}\)
= \(\dfrac{3}{5}\) \(\times\) ( \(\dfrac{7}{12}+\dfrac{5}{12}\))
= \(\dfrac{3}{5}\) \(\times\) \(\dfrac{12}{12}\)
= \(\dfrac{3}{5}\) \(\times\) 1
= \(\dfrac{3}{5}\)
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a)1440:40 =36
b)205 x 13 =2665
c)2057
d)36 x 25 x 4 =3600
18 x 24 :9 =48
41 x 2 x 8 x 5 =3280
215 x 86 + 215 x 14 =21500
53 x 128 - 43 x 128 =1408
2/3 x 4/7 =8/21
2 x 3 x 4 / 2 x 3 x 4 x 5 =24/120
1 x 2 x 3 x 4 / 5 x 6 x 7 x 8=24/1680
x : 7/11 = 22
x =22 x 7/11
x =14
2/7 * x =2/3
x = 2/7 :2/3
x = 20/21
\(\left(x+\frac{3}{10}\right)+\left(x+\frac{3}{40}\right)+\left(x+\frac{3}{88}\right)=\frac{31}{22}\)
\(x+\left(\frac{3}{10}+\frac{3}{40}+\frac{3}{88}\right)=\frac{31}{22}\)
\(x+\frac{9}{22}=\frac{31}{22}\)
\(x\) \(=\frac{31}{22}-\frac{9}{22}\)
\(x\) \(=\frac{22}{22}\)
\(x\) \(=1\)
\(HokTot!!!\)
x+3/10+x+3/40+x+3/88=31/22
x.3+(3/10+3/40+3/88)=31/22
x.3+9/22=31/22
x.3=31/22-9/22
x.3=1
x=1:3
x=1/3