Question

Tìm X

A. (X +1)+(X+2)+(X+3)+…+(X+ 100)=5750

B. X+(1+2+3+4+…+50)=2000

C. (X-1)+(X-2)+…+(X-100)=50

Answer 1

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

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

\(100x-5050=50\)

\(100x=50+5050\)

\(100x=5100\)

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

Answer 2

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

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

\(100x+5050=5750\)

\(100x=5750-5050\)

\(100x=700\)

\(\Rightarrow x=7\)

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

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

\(x+1275=2000\)

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

Answer 3

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

( x + x + ........ + ) - ( 1 + 2 + ..... + 100 ) = 50

100x - 5050 = 50

100x = 50 + 5050

100x = 5100

=> x = 5100/100 = 51

Answer 4

(x + x ......+x)-(1+2+......+100)=50

100x-5050 = 50

100x=50+5050

100x=5100

Answer 5

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

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

\(\Rightarrow100x+\left(100+1\right).100:2=5750\Rightarrow100x+5050=5750\)

\(\Rightarrow100x=5750-5050=600\Rightarrow x=600:100=6\)

Answer 6

\(\text{c , ( x - 1 ) + ( x - 2 ) + ...... + ( x - 100 ) = 50}\)

\(\text{( x + x + ........ + ) - ( 1 + 2 + ..... + 100 ) = 50}\)

\(\text{100x - 5050 = 50}\)

\(\text{100x = 50 + 5050}\)

\(\text{100x = 5100}\)

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

Answer 7

a) (x+1)+(x+2)+(x+3)+...+(x+100)=5750

<=> (x+x+...+x)+(1+2+3+...+100)=5750

<=> 100x+\(\frac{\left(100+1\right)\cdot100}{2}=5750\)

<=>100x+5050=5750

<=> 100x=700

<=> x=7

Vậy x=7

Answer 8

b)x+(1+2+...+50)=2000

<=> x+\(\frac{\left(50+1\right)\cdot50}{2}=2000\)

<=> \(x+1275=2000\)

<=> x=725

Vậy x=725