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\(\left(5x+1\right)^2=121\)

\(\left(5x+1\right)^2=\pm11^2\)

\(\Rightarrow\left[{}\begin{matrix}5x+1=-11\\5x+1=11\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}5x=-11-1\\5x=11-1\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}5x=-12\\5x=10\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=-\dfrac{12}{5}\\x=2\end{matrix}\right.\)

Vậy \(x\in\left\{-\dfrac{12}{5};2\right\}\)

\(\left(5x+1\right)^2=121\)

dou ?

ße .

K xdinhj SP:< me too

`(x - 2) . (3x - 5) = 0`

`TH1`

`x - 2 = 0`

`x = 2`

`TH2`

`3x - 5 = 0`

`3x       = 0 + 5`

`3x       = 5`

`x = 5/3`

Vậy `x`ϵ `{ 5/3 ; 2 }`

`(x + 1) + (x + 2) + ... + (x + 66) = 2607`

`(x + x + ... + x) + (1 + 2 + ... + 66) = 2607`

Số số hạng của dãy `1 + 2 +...+ 66` là:

` ( 66 - 1 ) : 1 + 1 = 66` (số hạng)

Tổng là:

` (66 + 1)  × 66 : 2 = 2211`

Ta có

` 66x + 2211 = 2607`

` 66x = 2601 - 2211`

` 66x = 390`

` x = 390 : 66`

` x = 390/66`

\(D=2^2-2.2.\left(-3\right)+\left(-3\right)^2\)

\(=4-2.2.\left(-3\right)+9\)

\(=4-4.\left(-3\right)+9\)

\(=4-\left(-12\right)+9\)

\(=4+12+9\)

\(=25\)

\(E=\left(-3\right)^3-3.\left(-3^2\right).2+3.\left(-3\right).2^2\)

\(=\left(-27\right)-3.9.2+3.\left(-3\right).4\)

\(=\left(-27\right)-54+\left(-36\right)\)

\(=\left(-54+-36\right)-27\)

\(=-90-27\)

\(=-117\)

\(F=\left(-5\right)^3+3.\left(-5\right)^2.3+3.\left(-5\right).3^2+3^3\)

\(=\left(-125\right)+3.25.3+3.\left(-5\right).9+27\)

\(=\left(-125\right)+150+\left(-135\right)+27\)

\(=\left[\left(-125\right)+\left(-135\right)\right]+150+27\)

\(=\left(-260\right)+150+27\)

\(=-110+27\)

\(=\left(-83\right)\)

Thanks bà nha! 

2 . 3^x = 10 . 3^12 + 8 . 27^4

 2 ‧ 3^x = 10 ‧ 3^12 + 8 ‧ (3^3)^4

2 ‧ 3^x = 10 ‧ 3^12 + 8 ‧ 3^12

2 ‧ 3^x = (10 + 8) ‧ 3^12

2 ‧ 3^x = 18 ‧ 3^12

Tự làm nốt nhé!

\(-\dfrac{1}{8}+-\dfrac{5}{3}\)

\(=-\dfrac{3}{24}+-\dfrac{40}{24}\)

\(=-\dfrac{43}{24}\)