\(x+2x+3x+...+9x+10x=385\)

\(x.\left(1+2+3+...+10\right)=385\)

\(55x=385\)

\(x=\frac{385}{55}\)

\(x=7\)

Vậy \(x=7\)

Tham khảo nhé~

           x.1 + x.2 + x.3 + ... + x.9 + x.10 = 385

x. ( 1 + 2 + 4 + 5 + 6 + 7 + 8 + 9 + 10 ) = 385

                                                      x. 55 = 385

                                                            x = 385 : 55

                                                            x = 7

x.1 + x.2 + x.3 + ... + x.9 + x.10 = 385

x. ( 1 + 2 + 4 + 5 + 6 + 7 + 8 + 9 + 10 ) = 385

                                                      x. 55 = 385

                                                            x = 385 : 55

                                                            x = 7

1. 385 x 385+ 385 x 615 = 385 ( 385 + 615)

                                       = 385 x 1000

                                       = 385000

2a) 6 x (X + 7545) = 28542 x6

      6X + 45270 = 171252

                    6X = 125982

                     x= 125982:6

                     x= 20997

b) (X : 4) x8 = 9 x 8

  ( X :4 ) x 8 = 72

           X : 4 = 72 :8

          X : 4 = 9

             x = 9 x 4

             X= 36\(\)

35 x 11 + 385 x 45 + 385 x 9 x 6 = 385 + 385 x 45 + 385 x 54 = 385 x (1 + 45 + 54) = 385 x 100 = 38 500

b) \(-2\dfrac{2}{3}:x=1\dfrac{7}{9}:0.8\\ -\dfrac{8}{3}:x=\dfrac{16}{9}:\dfrac{4}{5}\\ -\dfrac{8}{3}:x=\dfrac{16}{9}.\dfrac{5}{4}\\ -\dfrac{8}{3}:x=\dfrac{20}{9}\\ x=-\dfrac{8}{3}:\dfrac{20}{9}\\ x=-\dfrac{8}{3}.\dfrac{9}{20}\\ x=-\dfrac{6}{5}\)

\(2\dfrac{2}{3}x+3\dfrac{3}{4}x=\dfrac{385}{24}\)
\(\dfrac{8}{3}x+\dfrac{15}{4}x=\dfrac{385}{24}\)
\(x\left(\dfrac{8}{3}+\dfrac{15}{4}\right)=\dfrac{385}{24}\)
\(x\left(\dfrac{32}{12}+\dfrac{45}{12}\right)=\dfrac{385}{24}\)
\(x\left(\dfrac{77}{12}\right)=\dfrac{385}{24}\)
\(x=\dfrac{385}{24}:\dfrac{77}{12}\)
\(x=\dfrac{385}{24}.\dfrac{12}{77}\)
<Bạn tự viết phép tính nha>
\(x=\dfrac{5}{2}\)
Vậy \(x=\dfrac{5}{2}\)
Chúc bn hk tốt!!

a) \(2\dfrac{2}{3}x+3\dfrac{3}{4}x=\dfrac{385}{24}\\ \dfrac{8}{3}x+\dfrac{15}{4}x=\dfrac{385}{24}\\ \left(\dfrac{8}{3}+\dfrac{15}{4}\right)x=\dfrac{385}{24}\\ \left(\dfrac{32}{12}+\dfrac{45}{12}\right)x=\dfrac{385}{24}\\ \dfrac{77}{12}x=\dfrac{385}{24}\\ x=\dfrac{385}{24}:\dfrac{77}{12}\\ x=\dfrac{385}{24}.\dfrac{12}{77}\\ x=\dfrac{5}{2}\)

= 385 x 43 + [ 385 x ( 1 + 46 ) ] 

= 385 x 43 + 385 x 47 

= 385 x ( 43 + 47 )

= 385 x 90 = 34650

kb với mình đi

385 * 43 + ( 385 * 1 + 385 * 46 )=

=385 * ( 43 +46 +1 )

= 385 *     90

=34650

( x + x + x + ...+ x ) + ( 1 + 2 + 3 + ... + 10 ) = 385

x * 10 + 55 = 385

x * 10 = 385 - 55

x * 10 = 330

x = 330 : 10

x = 33

 Vậy x = 33 

(x + 1) + (x + 2) + (x + 3) +.....+(x + 10) = 385

=> 10x + (1 + 2 + 3 + 4 + ....+10) = 385

=> 10x + 55 = 385

=> 10x = 330

=> x = 33

\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+10\right)=385\)

\(\Rightarrow10x+\left(1+2+3+4+...+10\right)=385\)

\(\Rightarrow10x+\left(11.5\right)=385\)

\(\Rightarrow10x=385-55\)

\(\Rightarrow x=\frac{330}{10}=33\)

x.1 + x.2 + x.3 + .....+ x.10 = 385

=> x.( 1+2+3+4+5+6+7+8+9+10 ) = 385

=> x.55 = 385

=> x = 385 : 55 = 7

 Vậy x=7

 #hoktot# 

Ta có: x.1 + x.2 + x.3 + .... + x.10 = 385

=> x.(1 + 2 + 3 + .... + 10) = 385

=> x.55 = 385

=> x = 7

P/S : dấu "." là dấu nhân nha

Trả lời:

\(x\times1+x\times2+x\times3+...+x\times10=385\)

\(\Leftrightarrow x\times\left(1+2+3+....+10\right)=385\)

\(\Leftrightarrow x\times\left(10+1\right)\times\left[\left(10-1\right)\div1+1\right]\div2=385\)

\(\Leftrightarrow x\times11\times10\div2=385\)

\(\Leftrightarrow x\times55=385\)

\(\Leftrightarrow x=7\)

Vậy \(x=7\)