để \(\overline{13xy}⋮2;5\Rightarrow y=0\)

để\(\overline{13x0}⋮3;9\)

thì 1+3+x+0\(⋮9\)

=> \(3+x⋮9\)

=> x=6

vậy số cần tìm là 1360

1 mảnh giấy

\(\left(n+9\right)⋮\left(n+4\right)\)

=> \(\left(n+9\right)-\left(n+4\right)⋮\left(n+4\right)\)

=> \(\left(n+9-n-4\right)⋮\left(n+4\right)\)

=> \(5⋮\left(n+4\right)\)

=> \(n+4\inƯ\left(5\right)=\left\{1;5\right\}\)

tó có bảng sau

vậy x\(\in\left\{1\right\}\)

\(\left(x+3\right)⋮\left(x+2\right)\)

=> \(\left(x+3\right)-\left(x+2\right)⋮\left(x+2\right)\)

=> \(\left(x+3-x-2\right)⋮\left(x+2\right)\)

=> \(1⋮\left(x+2\right)\)

=> \(x+2\inƯ\left(1\right)=\left\{\pm1\right\}\)

ta có bảng sau

vậy x=-3 hoặc x=-1

: x³-2x-4

= x³+0x²-2x-4

= x³-2x²+2x²-4x+2x-4

=(x³-2x²)+(2x²-4x)+(2x-4)

= x²(x-2)+2x(x-2)+2(x-2)

= (x-2)(x²+2x+2)

Trước khi bán cửa hàng có số lít nước mắm là: 123,5x100:9,5=1300 (lít)

tick mik nha bạn

a) 7x²+7xy-x-y

=(7x2-x)+(7xy-y)

=x(7x-1)+y(7x-1)

=(7x-1)(x+y)

b) 2x²+3x-5

=2x²+5x-2x-5

=x(2x+5)-1(2x+5)

=(x-1)(2x+5)

a) 27x³+8

= (3x)³+2³

=(3x+2)(9x²-6x+4)

b,x²-2xy+y²-3x+3y

=(x²-2xy+y²)-(3x-3y)

= (x-y)²-3(x-y)

= (x-y)(x-y-3)

c. x³-3x+2

= x³+0x²-3x+2

=x³+2x²-2x²-4x+x+2

=(x³+2x²)-(2x²+4x)+(x+2)

= x²(x+2)-2x(x+2)+(x+2)

=(x+2)(x²-2x+1)

=(x+2)(x-1)²

x³-16x=0

=> x(x²-16)=0

=> x(x-4)(x+4)=0

=> \(\left[{}\begin{matrix}x=0\\x-4=0\\x+4=0\end{matrix}\right.\) => \(\left[{}\begin{matrix}x=0\\x=4\\x=-4\end{matrix}\right.\)

vậy x=0 ;x=4;x=-4

3x(2-x)-2+x=0

=> 3x(2-x)-(2-x)=0

=> (2-x)(3x-1)=0

=> \(\left[{}\begin{matrix}2-x=0\\3x-1=0\end{matrix}\right.\) => \(\left[{}\begin{matrix}x=2\\3x=1\Rightarrow x=\dfrac{1}{3}\end{matrix}\right.\)

vậy x=2 hoặc x=\(\dfrac{1}{3}\)

$5.\left(x+4\right)+38=123$

$\mathrm{=>\; 5(x+4)=123-38}$

$\mathrm{=>\; 5(x+4)=85}$

$\mathrm{=>\; x+4=85:5}$

$\mathrm{=>x+4=17}$

$\mathrm{=>\; x=17-4}$

=> x=13