\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+.....+\left(x+100\right)=5750\)
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\(\left(x+1\right)+\left(x+2\right)+...+\left(x+100\right)=5750\)
\(\left(x\cdot100\right)+\left(1+2+...+100\right)=5750\)
\(\left(x\cdot100\right)+\left(100+1\right)\cdot\frac{100}{2}=5750\)
\(\left(x\cdot100\right)+101\cdot50=5750\)
\(\left(x\cdot100\right)+5050=5750\)
\(x\cdot100=5750-5050\)
\(x\cdot100=700\)
\(x=700\div100\)
\(x=7\)
Ta có: ( x+1)+(x+2)+(x+3)+.....+(x+99)+(x+100)=5750
<=>(x+x+x+....+x+x)+(1+2+3+..+99+100)=5750
<=> 100x+5050=5750
=>100x=5750-5050
=>100x=700
=>x=700:100
=>x=7
Vậy x=7
hoặc mở câu hỏi tương tự tham khảo.
=(x+x+...+x)+(1+2+...+100)=5750
=100x+5050=5750
100x=5750-5050
100x=700
x=700/100=7
(x+1)+(x+2)+....+(x+100)=5750
x+1+x+2+...+x+100 =5750
\(x\)x100+1+2+...+100 =5750
bí hihi
tự làm nha
\(\left(x+1\right)+\left(x+2\right)+.....+\left(x+100\right)=5750\)
\(\Rightarrow x+1+x+2+.....+x+100=5750\)
\(\Rightarrow100x+1+2+3+....+100=5750\)
\(\Rightarrow100x+\left[\left(\dfrac{100-1}{1}+1\right):2\right]\left(100+1\right)=5750\)
\(\Rightarrow100x+5050=5750\)
\(\Rightarrow100x=700\)
\(\Rightarrow x=7\)
\(\left(x+1\right)+\left(x+2\right)+...+\left(x+100\right)=5750\)
\(\left(x+x+x+...+x\right)+\left(1+2+...+100\right)=5750\)
\(100x+5050=5750\)
\(100x=5750-5050\)
\(100x=700\)
\(x=7\)
Vậy ...
\(a)\) \(A=4+2^2+2^3+...+2^{20}\)
\(A=2^2+2^2+2^3+...+2^{20}\)
\(2A=2^3+2^3+2^4+...+2^{21}\)
\(2A-A=\left(2^3+2^3+2^4+...+2^{21}\right)-\left(2^2+2^2+2^3+...+2^{20}\right)\)
\(A=2^3+2^{21}-2^2-2^2\)
\(A=2^3+2^{21}-2.2^2\)
\(A=2^3+2^{21}-2^3\)
\(A=2^{21}\)
Vậy \(A=2^{21}\)
\(b)\) \(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+100\right)=5750\)
\(\Leftrightarrow\)\(\left(x+x+x+...+x\right)+\left(1+2+3+...+100\right)=5750\)
\(\Leftrightarrow\)\(100x+\frac{100\left(100+1\right)}{2}=5750\)
\(\Leftrightarrow\)\(100x+5050=5750\)
\(\Leftrightarrow\)\(100x=5750-5050\)
\(\Leftrightarrow\)\(100x=700\)
\(\Leftrightarrow\)\(x=\frac{700}{100}\)
\(\Leftrightarrow\)\(x=7\)
Vậy \(x=7\)
Chúc bạn học tốt ~
a, Vì trong mỗi ngoặc có một số hạng nên vì có 100 số hạng nên có 100x
ta có 100x+(1+2+3+.....+100)=5750
100x+5050=5750
100x=5750-5050
100x=700
x=700:100
x=7
nếu tính ko nhầm
a)(x+1)+(x+2)+...+(x+100)=5750
(x+x+...+x)+(1+2+...+100)=5750
1+2+...+100 có: (100-1)+1 =100 số hạng
1+2+...+100=(100+1)*100/2=5050
=>100x+5050=5750
100x=5750-5050
100x=700
x=700/100
x=7. Vậy x=7
c) (x+1) + (x+2) + ... + (x+5) = 90
=> 5x + ( 1 + 2 + ... + 5 ) = 90
5x + 15 = 90
5x = 90 - 15
5x = 75
x = 75 : 5
x = 15
d) (x+1) + (x+2) + .... + (x+100) = 20150
=> 100x + ( 1+2+...+100 ) = 20150
100x + 5050 = 20150
100x = 20150 - 5050
100x = 15100
x = 15100 : 100
x = 151
Ta có : (x + 1) + (x + 2) + (x + 3) + (x + 4) + (x + 5) = 90
<=> x + x + x+ x + x + (1 + 2 + 3 + 4 + 5) = 90
<=> 5x + 15 = 90
=> 5x = 75
=> x = 15
Phân thức cuối hình như mẫu sai rồi bạn
Phải là (x+9)(x+10) mới đúng chứ
\(\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x+2\right)}+\frac{1}{\left(x+2\right)\left(x+3\right)}+.....+\frac{1}{\left(x+99\right)\left(x+100\right)}\)
\(=\frac{1}{x}-\frac{1}{x+1}+\frac{1}{x+1}-\frac{1}{x+2}+\frac{1}{x+2}-\frac{1}{x+3}+.....+\frac{1}{x+99}-\frac{1}{x+100}\)
\(=\frac{1}{x}-\frac{1}{x+100}\)
\(=\frac{1}{x}-\frac{1}{x+1}+\frac{1}{x+1}-\frac{1}{x+2}+...+\frac{1}{x+99}-\frac{1}{x+100}=\frac{1}{x}-\frac{1}{x+100}=\frac{x+100-x}{x\left(x+100\right)}=\frac{100}{x\left(x+100\right)}\)
=> x + 1 + x + 2 + ... + x + 100 = 5750
=> ( x + x + ... + x ) + ( 1 + 2 + .... + 100 ) = 5750
=> 100x + 5050 = 5750
=> 100x = 5750 - 5050
=> 100x = 700
=> x = 7 00 : 100
=> x = 7
x + x + x + x + ....+x +x + 1 + 2 + 3 + .... + 100 = 5750
100x + 5050 = 5750
100x = 5750 - 5050
100x = 700
x = 700 : 100
x = 7