các bạn giúp m với =(((((

(x+1)+(x+2)+(x+3)+....+(x+15)+(x+16)=154

=>(x+x+...+x)+(1+2+...+16)=154

=>16x+136=154

=>16x=18

=>x=1,125 (hình như đề sai)

\(\dfrac{1}{x^2+7x+10}+\dfrac{1}{x^2+13x+40}+\dfrac{1}{x^2+19x+88}+\dfrac{1}{x^2+25x+154}\)

\(=\dfrac{1}{\left(x+2\right)\left(x+5\right)}+\dfrac{1}{\left(x+5\right)\left(x+8\right)}+\dfrac{1}{\left(x+8\right)\left(x+11\right)}+\dfrac{1}{\left(x+11\right)\left(x+14\right)}\)

\(=\dfrac{1}{x+2}-\dfrac{1}{x+5}+\dfrac{1}{x+5}-\dfrac{1}{x+8}+\dfrac{1}{x+8}-\dfrac{1}{x+11}+\dfrac{1}{x+11}-\dfrac{1}{x+14}\)

\(=\dfrac{1}{x+2}-\dfrac{1}{x+14}\)

$ a/ 12x(x – 5) – 3x(4x - 10) = 120$

`<=>12x^2-60x-12x^2+30x=120`

`<=>-30x=120`

`<=>x=-4`

Vậy `x=-4`

$b/ 9x(x + 4) – 5x(3x + 2) = 112 - 2x(3x + 1)$

`<=>9x^2+36x-15x^2-10x=112-6x^2-2x`

`<=>-6x^2+26x=112-6x^2-2x`

`<=>28x=112`

`<=>x=4`

Vậy `x=4`

$c/ 3x(1 – x) - 5x(3x + 7) = 154 + 9x(5 – 2x)$

`<=>3x-3x^2-15x^2-35x=154+45x-18x^2`

`<=>-32x-18x^2=154+45x-18x^2`

`<=>77x=-154`

`<=>x=-2`

Vậy `x=-2`

x=516

x=31669

x=\(\frac{23}{3}\)

x=\(\frac{25}{6}\)

x+453-13440:14=964

x+453-960=964

x+453=964+960=1924

x=1924-453=1471

x-37x11=154x203

x-407=31262

x=31262+407=31669

4-\(\frac{1}{2}\)x=\(\frac{1}{6}\)

\(\frac{1}{2}\)x=4-\(\frac{1}{6}\)=\(\frac{23}{6}\)

x=\(\frac{23}{6}\):\(\frac{1}{2}\)=\(\frac{23}{3}\)

\(\frac{1}{3}\)+x=\(\frac{3}{2}\)x3=\(\frac{9}{2}\)

x=\(\frac{9}{2}\)-\(\frac{1}{3}\)=\(\frac{25}{6}\)

a) Số các số hạng :

[(x + 16) - (x + 1)] + 1 = 16 (số hạng)

Tổng trên là :

[(x + 16) + (x + 1)] x 16 : 2 = (2x + 17) x 16 : 2 = 154

=> (2x + 17) x 16 = 208

=> 2x + 7 = 13

=> 2x = 20

=> x = 10

a) ( x + 1 ) + ( x + 2 ) + ( x + 3 ) + .... + ( x + 16 ) = 154

=> x + 1 + x + 2 + x + 3 + ... + x + 16 = 154

=> ( x + x + x + ... + x ) + ( 1 + 2 + 3 + ... + 16 ) = 154

=> 16x + 136 = 154

=> x = ( 154 - 136 ) : 16

=> x = 9/8

b) ( x + 1 ) + ( x + 3 ) + ( x + 5 ) + ... + ( x + 19 ) = 245

=> x + 1 + x + 3 + x + 5 + ... + x + 19 = 245

=> ( x + x + x + ... + x ) + ( 1 + 3 + 5 + ... + 19 ) = 245

=> 10x + 100 = 245

=> x = ( 245 - 100 ) : 10

=> x = 9/2