Trả lời:

a, x . ( 2013 + 2014 + 2015 ) = 0

=> x = 0 : ( 2013 + 2014 + 2015 )

=> x = 0

Vậy x = 0

b, x . 125 = 10000

=> x = 10000 : 125

=> x = 80

Vậy x = 80

c, 697 : [ ( 15 . x + 364 ) : x ] = 17 

=> ( 15 . x + 364 ) : x = 697 : 17

=> ( 15 . x + 364 ) : x = 41 

=> 15 . x + 364 = 41 . x

=> 41 . x - 15 . x = 364

=> ( 41 - 15 ) . x = 364

=> 26 . x = 364

=> x = 364 : 26

=> x = 14

Vậy x = 14

Giải:

\(B=\left(5+10+15+...+2015\right)\times\left(20142014\times2015-20152015\times2014\right)\) 

\(B=\left(5+10+15+...+2015\right)\times\left(10001\times2014\times2015-10001\times2015\times2014\right)\)

\(B=\left(5+10+15+...+2015\right)\times0\) 

\(B=0\) 

Chúc em học tốt!

B = (5+10+15+.........+2015) x (20142014 x 2015-20152015 x 2014)

Với x = 2014 => x + 1 = 2015

Ta có : 

\(f\left(x\right)=x^{17}-2015x^{16}+2015x^{15}-2015x^{14}+....+2015x-1\)

<=>  \(f\left(x\right)=x^{17}-\left(x+1\right)x^{16}+\left(x+1\right)x^{15}-\left(x+1\right)x^{14}+....+\left(x+1\right)x-1\)

<=> \(f\left(x\right)=x-1\)

<=> \(f\left(2014\right)=2014-1=2013\)

Sửa đề: \(\dfrac{x+2}{2014}+\dfrac{x+1}{2015}=\dfrac{x+2001}{15}+\dfrac{x+2014}{2}\)
Ta có: \(\dfrac{x+2}{2014}+\dfrac{x+1}{2015}=\dfrac{x+2001}{15}+\dfrac{x+2014}{2}\)

\(\Leftrightarrow\dfrac{x+2}{2014}+1+\dfrac{x+1}{2015}+1=\dfrac{x+2001}{15}+1+\dfrac{x+2014}{2}+1\)

\(\Leftrightarrow\dfrac{x+2016}{2014}+\dfrac{x+2016}{2015}=\dfrac{x+2016}{15}+\dfrac{x+2016}{2}\)

\(\Leftrightarrow\dfrac{x+2016}{2014}+\dfrac{x+2016}{2015}-\dfrac{x+2016}{15}-\dfrac{x+2016}{2}=0\)

\(\Leftrightarrow\left(x+2016\right)\left(\dfrac{1}{2014}+\dfrac{1}{2015}-\dfrac{1}{15}-\dfrac{1}{2}\right)=0\)

mà \(\dfrac{1}{2014}+\dfrac{1}{2015}-\dfrac{1}{15}-\dfrac{1}{2}\ne0\)

nên x+2016=0

hay x=-2016

Vậy: S={-2016}

=6100414.985

Đ/s: 8114414,985

6100414.985

\(\frac{x-2014}{14}-\frac{x-2015}{15}=0\)

<=> \(\frac{15\left(x-2014\right)}{14\cdot15}-\frac{14\left(x-2015\right)}{14\cdot15}=0\)

<=> \(15x-30210-14x+28210=0\)

<=> \(x-2000=0\)

<=> \(x=2000\)

Vậy nghiệm của phương trình là S = { 2000 }

x-(2014/14-2015/15)=0

x-200/21=0

x=0+200/21

x=200/21

a) => (4x-15).(4x-15)²⁰¹⁵=(4x-15)²⁰¹⁵

=> 4x-15=1

=> x=4

b) => 4.2^x+6-480= 0

=> 4.2^x-474=0

=> 4.2^x=474

=> 2^x= 118,5

ko có gt x thoả mãn đề bài

chả biết câu b trình bày đúng hay sai, hay là đầu bài chép nhầm nữa. Nếu sai ai đó chữa lại hộ cái nhé

                                                                              _HẾT_

b, 2^x+2^x+1+2^x+2+2^x+3-480=0

2^x.1+2^x.2+2^x.2^2+2^x.2^3=480

2^x.(1+2+2^2+2^3)=480

2^x.15=480

2^x=32

2^x=2^5

x=5

cau thu nhat 

x = 1

cau thu hai

x = -2015

dua nao tra loi ma ngu the

viet ro cach lam ra chu