Câu 1 : Tìm số tự nhiên a , biết :

( a + 1 ) + ( a + 2 )  +  ( a + 3 ) +...+ ( a + 49 ) + (  a + 50 ) = 2525

(a+a+...+a) +(1+2+3+...+50)=2525

50 SH a

50 . a+(50+1).25=2525

50.a + 1275=2525

50.a=2525-1275

50.a=1250

a=1250:50

=>a=25

TICK ĐI RỒI MIK LÀM TIẾP CHO

So so hang la (50-1):1+1=50(so hang)

(a+a+a+...+a)+(1+2+3+...+50)=2525

(a*50)+(50+1)*50:2=2525

a*50+1275=2525

a*50=2525-1275

a*50=1250

a=1250:50

a=25

1:

13*2525-25*1313

=13*25*(101-101)

=0

`@` `\text {Ans}`

`\downarrow`

`1.`

`13 \times 2525 - 25 \times 1313`

`= 13 \times 101 \times 25 - 25 \times 13 \times 101`

`= 13 \times 25 \times ( 101 - 101)`

`= 13 \times 25 \times 0`

`= 0`

`2.`

`(4 \times x - 2) \times (2024 - x) = x`

`4x(2024 - x) - 2(2024 - x) - x = 0`

`4x \times 2024 - 4x \times x - [ 2 \times 2024 + 2 \times (-x) ] = 0`

`8096 - 4x \times x - (4048 - 2x) = 0`

`8096 - 4x \times x - 4048 + 2x = 0`

`4048 - x(4x + 2) = 0`

`x(4x + 2) = 4048`

Bạn xem lại đề ;-; mình nghĩ lp 5 chưa hc mấy dạng ntnay ;-;.

81 + 243 + 19

= ( 81 + 19 ) + 243

= 100 + 243

= 343

( x - 2525 - 2525 ) +6262 + 321 = 10000

 ( x - 5050 ) + 6583 = 10000

  x - 5050 = 3417

  x = 8467

315 \(x\)(46-x) = 401

  46 - x = \(\frac{401}{305}\)

   -x =\(-\frac{13629}{305}\)

    x = \(\frac{13629}{305}\)

49  \(x\)313 + 187  \(x\)7² +350

=14398 + 9163 + 350

=23911

250 - 160 - ( 18 - 12 ) ²

= 90 - 6²

=54

\(x\)là nhân nha

chúc bn học tốt

\(\dfrac{2929}{2525}\cdot\dfrac{505050}{848484}\cdot\dfrac{42}{29}\)

\(=\dfrac{29}{25}\cdot\dfrac{50}{84}\cdot\dfrac{42}{29}\)

\(=\dfrac{29}{29}\cdot\dfrac{50}{25}\cdot\dfrac{42}{84}=1\cdot2\cdot\dfrac{1}{2}=1\)

1) 1/2*1/6=1/12 ; 1/3*1/4=1/12. Ta có : 17/5+1/12*71/5-1/12*28/5=1/12*(17/5+71/5-28/5)=1/12*60/5=1/12*12=1      2)1/10+4/20+9/30+16/40+25/50                   =1/10+2/10+3/10+4/10+5/10(rút gọn)            =15/10=3/2                                               3)18/15*(2525/3636+1515/1818-2020/7272)=6/5*(25/36+5/6-5/18)(rút gọn)=6/5*25/36+6/5*5/6-6/5*5/18=5/6+1-1/3=9/6=3/2.

\(c,\)\(\left(x-1\right)+\left(x-2\right)+....+\left(x-100\right)=50\)

\(\left(x+x+...+x\right)-\left(1+2+...+100\right)=50\)

\(100x-5050=50\)

\(100x=50+5050\)

\(100x=5100\)

\(\Rightarrow x=\frac{5100}{100}=51\)

\(a,\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+....+\left(x+100\right)=5750\)

\(\left(x+x+x+...+x\right)+\left(1+2+3+...+100\right)=5750\)

\(100x+5050=5750\)

\(100x=5750-5050\)

\(100x=700\)

\(\Rightarrow x=7\)

\(b,x+\left(1+2+3+...+50\right)=2000\)

 \(x+\frac{\left[1+50\right]\cdot\left[\left(50-1\right)\div1+1\right]}{2}=2000\)

\(x+1275=2000\)

\(\Rightarrow x=2000-1275=725\)

bằng 26 là sai đấy phải là 19 cơ

x51=25 nha