Bài 1.

\(x\times15+x\times35=250\)

\(x\times\left(15+35\right)=250\)

\(x\times50=250\)

\(x=250:50\)

\(x=5\)

\(------\)

\(718-x\times5=173\)

\(x\times5=718-173\)

\(x\times5=545\)

\(x=545:5\)

\(x=109\)

\(x\times15+x\times35=250 \\ x\times\left(15+35\right)=250\\ x\times50=250\\ x=250:50\\ x=5\\ 718-x\times5=173\\ x\times5=718-173\\ x\times5=545\\ x=545:5\\ x=109\)

\(x^{15}=x\\\Rightarrow x^{15}-x=0\\\Rightarrow x(x^{14}-1)=0\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x^{14}-1=0\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x^{14}=1\end{matrix}\right.\)

\(\Rightarrow\left[{}\begin{matrix}x=0\\x=1\\x=-1\end{matrix}\right.\)

Vậy: \(x\in\left\{0;1;-1\right\}\)

x¹⁵ = x

x¹⁵ - x = 0

x.(x¹⁴ - 1) = 0

x = 0 hoặc x¹⁴ - 1 = 0

*) x¹⁴ - 1 = 0

x¹⁴ = 1

x = 1 hoặc x = -1

Vậy x = 0; x = -1; x = 1

x=1 ạ

Đáp án A

a ) x − 1 2 = 7 13 . 13 28 ; x − 1 2 = 1 4 b ) x 15 = − 3 11 . 77 36 ; x 15 = − 7 12 ; x = 15. − 7 12 c ) x + 7 7 = 9 18 . 9 27 ; x + 1 = 1 6 d ) x : 15 11 = − 3 12 .8 ; x : 15 11 = − 2 ; x = ( − 2 ) . 15 11

(x-34)x15=0

=>x-34=0:15=0

=>x=0+34

=>x=34

a) x = 1.           

b) x = 6.              

c)x = - ll.

Đáp án là B

x15+32x+x1=780

xxx+(15+320+1)=780

xxx+336    =780

xxx           = 780-336  

xxx             = 444

<=>x.(15+32+1)=780

<=>x.48           =780

<=>x                =780:48

<=>x                =16,25

Vậy x=15,25

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