112/34=56/x

<=>56/17=56/x

=>x=17

Chúc bạn học giỏi nha

k cho mik với nhé Be Chip

Ta có:

\(\frac{112}{34}=\frac{56}{x}\)

\(\Rightarrow112.x=56.34\)

\(\Rightarrow112.x=1904\)

\(\Rightarrow x=1904:112\)

\(\Rightarrow x=17\)

Vậy x = 17

Giải rõ ràng. Không được thử số

Ta có : \(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{x\left(x+2\right)}=\frac{16}{34}\)

=> \(2\left(\frac{1}{1.3}+\frac{1}{3.5}+\frac{1}{5.7}+...+\frac{1}{x\left(x+2\right)}\right)=2.\frac{16}{34}\)

=> \(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{x\left(x+2\right)}=\frac{16}{17}\)

=> \(\frac{1}{1}-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{x}-\frac{1}{x+2}=\frac{16}{17}\)

=> \(1-\frac{1}{x+2}=\frac{16}{17}\)

=> \(\frac{1}{x+2}=1-\frac{16}{17}=\frac{1}{17}\)

=> \(x+2=17\)

=> \(x=15\)

=>1/1-1/3+1/3-1/5+1/5-1/7+....+1/x-1/(x+2)=16/34

=>1/1-1/(x+2)=16/34

=>1/(x+2)=1-16/34

=>1/(x+2)=9/17

=>(x+2).9=17

=>(x+2)=17/9

=>x=17/9-2

=>x=-1/9(không là số tự nhiên)

vậy không có số tự nhiên x thoả mãn điều kiện bài toán 

[(x+34)-50].2=56

`<=>(x+34-50).2=56

`<=>(x-16).2=56

`<=>2x-32=56

`<=>2x=56+32

`<=>2x=88

Ta có: \(\left(x+34-50\right)\cdot2=56\)

\(\Leftrightarrow x-16=28\)

hay x=44

bài 1

[(x+2)/10¹⁰]+ [(x+2)/11¹¹]= [(x+2)/12¹²]+[(x+2)/13¹³]

=>[(x+2)/10¹⁰]+[(x+2)/11¹¹] - [(x+2)/12¹²]-[(x+2)/13¹³] = 0

=>(x+2).[(1/10¹⁰)+(1/11¹¹)-(1/12¹²)-(1/13¹³)=0

Vì [(1/10¹⁰)+(1/11¹¹)-(1/12¹²)-(1/13¹³)] khác 0

=>x+2=0

=>x=-2

Bài 1: x=-2

Bài 2:x=17

Bài 3:x=2014

y=2010

ta nhân vế trái vs 2:

\(\frac{2}{1.3}+\frac{2}{3.5}+......+\frac{2}{x\left(x+2\right)}=\frac{8}{17}\)

\(\frac{1}{ }-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+.....+\frac{1}{x}-\frac{1}{x+2}=\frac{8}{17}\)

\(1-\frac{1}{x+2}=\frac{8}{17}\)

\(\Rightarrow17\left(x+1\right)=8\left(x+2\right)\)

\(\Rightarrow17x+17=8x+16\)

\(\Rightarrow17x-8x=-17+16\)

\(\Rightarrow9x=-1\)

\(\Rightarrow x=\frac{-1}{9}\)

2(1/1.3+1/3.5+1/5.7+...+1/x(x+2) )=16/34 *2

2/1.3+2/3.5+2/5.7+...+2/x(x+2)=32/34=16/17

1/1-1/3+1/3-1/5+1/5-1/7+...+1/x-1/x+2=16/17

1/1-1/x+2=16/17

1/x+2=1/1-16/17

1/x+2=1/17

suy ra x+2=17

         x=17=2=15

Ta có\(\frac{1}{1\cdot3}\) +\(\frac{1}{3\cdot5}\)+\(\frac{1}{5\cdot7}\)+.....+\(\frac{1}{x\cdot\left(x+2\right)}\)=\(\frac{16}{34}\)

=> 2(\(\frac{1}{1\cdot3}\)+\(\frac{1}{3\cdot5}\)+\(\frac{1}{5\cdot7}\)+......+\(\frac{1}{x+\left(x+2\right)}\)) = \(\frac{16}{34}\)*2

=>  \(\frac{2}{1\cdot3}\)+\(\frac{2}{3\cdot5}\)+\(\frac{2}{5\cdot7}\)+.....+\(\frac{2}{x\cdot\left(x+2\right)}\)= \(\frac{32}{34}\)

1-\(\frac{1}{3}\)+\(\frac{1}{3}\)-\(\frac{1}{5}\)+\(\frac{1}{5}\)-\(\frac{1}{7}\)+.....+\(\frac{1}{x}\)-\(\frac{1}{x+2}\)=\(\frac{32}{34}\)

1-\(\frac{1}{x+2}\)=\(\frac{32}{34}\)

\(\frac{1}{x+2}\)= 1-\(\frac{32}{34}\)

\(\frac{1}{x+2}\)= \(\frac{1}{17}\)

=> x+2=17

x=17-2 

x=15