Ta có: \(\left(x-3\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+9\left(x+1\right)^2=15\)

⇔  \(x^3-9x^2\)+  27x  −  27  −\(x^3\)+  27  +\(9x^2\)+  18x  +  9  =  15

⇔  45x  =  6

hay \(x=\frac{2}{15}\)

x = 2/15

a/ 1097 x 32 + 1097 x 67 + 1097

= 1097 x ( 32 + 67 +1)

= 1097 x 100

= 10970

b/ 846 x 95 + 3 x 846 + 846 + 846

= 846 x ( 95 + 3 + 1+ 1)

= 846 x 100

=  84600

1097⋅32+1097⋅67+1097

1097(32+67+1)=1097x100=109700

846 x 95 + 3 x 846 + 846 + 846

846x(95+3+1+1)=846x100=84600

Nhầm xíu :>>

Đặt \(A=\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{1}{55}\)

\(\Rightarrow\frac{1}{2}A=\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{110}\)

\(\Rightarrow\frac{1}{2}A=\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+...+\frac{1}{10\times11}\)

\(\Rightarrow\frac{1}{2}A=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{10}-\frac{1}{11}\)

\(\Rightarrow\frac{1}{2}A=\frac{1}{2}-\frac{1}{11}\Rightarrow\frac{1}{2}A=\frac{9}{22}\Rightarrow A=\frac{9}{11}\)

Đặt \(A=\frac{1}{3}+\frac{1}{6}+\frac{1}{10}+...+\frac{1}{55}\)

\(\Rightarrow2A=\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{110}\)

\(\Rightarrow2A=\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+...+\frac{1}{10\times11}\)

\(\Rightarrow2A=\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+...+\frac{1}{10}-\frac{1}{11}\)

\(\Rightarrow2A=\frac{1}{2}-\frac{1}{11}\Rightarrow2A=\frac{9}{22}\Rightarrow A=\frac{9}{44}\)

S=1 + 3 + 5 + ... + 99 + 101

=> S = ( 101 + 1 ) . 51 : 2

=> S = 102 . 51 ; 2

=> S = 5202 : 2

=> S = 2601

Ta có: 1+3+5+...+99+101

Tổng trên là:(1+101).2= 204

Đ/S: 204

k cho mk nha!!!!

6.7.168 – 14.85.3 + 17.21.2

= 42 . 168 - 42 . 85 + 42 . 17

= 42 . ( 168 - 85 + 17 )

= 42 . 100

= 4200

= 2.3.7.168 - 2.7.85.3 + 17.2.21

= 21.336 - 21.170 + 21.34

= 21.( 336 + 34 - 170 )

= 21.200

= 4200

5.649717514124294... × 177 = 1000

177×_^​1000/177=1000 nha​​

\(\left|2x-4\right|=\left|5x+3\right|\)

\(\Rightarrow\orbr{\begin{cases}2x-4=5x+3\\2x-4=-5x+3\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}2x-4=5x+3\\2x-5x=-5x-3\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}2x-5x=3+4\\2x+5x=-3+4\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}-3x=7\\7x=1\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=\frac{-7}{3}\\x=\frac{1}{7}\end{cases}}\)

( 57 - 3 × X ) × 12 - 24 = 47 × 2 - 82

( 57 - 3 × X ) × 12 - 24 = 94 - 82

( 57 - 3 × X ) × 12 - 24 = 12

( 57 - 3 × X ) × 12 = 12 + 24

( 57 - 3 × X ) × 12 = 36

57 - 3 × X = 36 : 12

57 - 3 × X = 3

3 × X = 57 - 3

3 × X = 54

      X = 54 : 3

      X = 18

( 57 - 3 × X ) × 12 - 24 = 47 × 2 - 82

= ( 57 - 3 × X ) × 12 - 24 = 94 - 82

= ( 57 - 3 × X ) × 12 - 24 = 12

= ( 57 - 3 × X ) × 12 = 12 + 24

= ( 57 - 3 × X ) × 12 = 36

= 57 - 3 × X = 36 : 12

= 57 - 3 × X = 3

= 3 × X = 57 - 3

= 3 × X = 54

      X = 54 : 3

      X = 18