3 + 4 + 5 + 6 + ... + x = 52

Suy ra [(3 + x) * (x - 2)] : 2 = 52

(3 + x ) * (x - 2) = 52 * 2 = 104

(3 + x) * (x - 2) = 13 * 8

Suy ra x = 10

Vậy x = 10

3 + 4 + 5 + 6 + ... + 10 = 52

=> x-\(\frac{4}{5}\)=0               hoặc \(x+2\frac{1}{5}=0\)

 => \(x=\frac{4}{5}\)                    \(x=-2\frac{1}{5}\)

mơn nheee

Các bạn giải giúp mik với ạ nhanh lên mik sắp pải nộp cho cô rùi 

1+1=3

a,x=2/15

b,x=1/20

c=6/5

d.x=144/5

\(\frac{7}{4}-x+\frac{4}{3}=\frac{5}{19}\)

\(\Rightarrow\frac{7}{4}-x=\frac{5}{19}-\frac{4}{3}\)

\(\Rightarrow\frac{7}{4}-x=-\frac{61}{57}\)

\(\Rightarrow x=\frac{7}{4}+\frac{61}{57}\)

\(\Rightarrow x=???\)

tíc mình nha

Bài giải

Số số hạng là:

(2026-1):1+1=2026

Tổng là:

(1+2026) x 2026 : 2= 2053351

Đáp số: 2053351

Mik cũng lớp năm nên mik giải theo cách cấp 1 nha, đôi lúc vẫn có sai sót mong bạn thông cảm!

Số số hạng trong dãy số 1;2;3;4;5;6;...;2023;2024;2025 là:

(2025-1):1+1=2025(số)

A=1+2-3+4+5-6+...+2023+2024-2025+2026

=(1+2-3)+(4+5-6)+...+(2023+2024-2025)+2026

=0+3+...+2022+2026

=3+6+...+2022+2026

\(=3\left(1+2+\cdots+674\right)+2026\)

\(=3\times674\times\frac{675}{2}+2026=684451\)

a) \(\left(x+\frac{3}{4}\right):5=\frac{5}{6}\)

\(x+\frac{3}{4}=\frac{5}{6}\text{x}5\)

\(x+\frac{3}{4}=\frac{25}{6}\)

\(x=\frac{25}{6}-\frac{3}{4}\)

\(x=\frac{41}{12}\)

b) \(\left(\frac{4}{3}+x\right)\text{x}\frac{1}{11}=\frac{7}{11}\)

\(\frac{4}{3}+x=\frac{7}{11}:\frac{1}{11}\)

\(\frac{4}{3}+x=7\)

\(x=7-\frac{4}{3}\)

\(x=\frac{17}{3}\)

a) \(x+\frac{3}{4}\div5=\frac{5}{6}\)

\(x+\frac{3}{4}=\frac{5}{6}\times5\)

\(x+\frac{3}{4}=\frac{25}{6}\)

\(x=\frac{25}{6}-\frac{3}{4}\)

\(x=\frac{41}{21}\)

b) \(\left(\frac{4}{3}+x\right)\times\frac{1}{11}=\frac{7}{11}\)

\(\frac{4}{3}+x=\frac{7}{11}\div\frac{1}{11}\)

\(\frac{4}{3}+x=7\)

\(x=7-\frac{4}{3}\)

\(x=\frac{17}{3}\)

2/3 x 4/5 x 25 = 8/15 x 25 = 40/3

\(x\) x\(\dfrac{1}{2}\)+\(\dfrac{1}{4}\)-\(\dfrac{1}{5}\)= 55

\(x\) x \(\dfrac{11}{20}\)       = 55

\(x\)                = 55 : \(\dfrac{11}{20}\)

\(x\)                =100

CÁCH LÀM NHƯ SAU : 

(7/28 + 1/28) + 1/70 + 1/130 + 1/x.(x+3)

8/28 + 1/70 +1/130 +1/x.(x+3)

2/7+1/70+1/130+1/x.(x+3)

(20/70 +1/70)+1/130+1/x.(x+3)

3/10+1/130+1/x.(x+3)

39/130+1/130+1/x.(x+3)

4/13+1/x.(x+3)

Đến đây bn tự làm hộ mình vớ. chúc hok tốt k cho mình nhé

\(\frac{1}{4}+\frac{1}{28}+\frac{1}{70}+\frac{1}{130}+\frac{1}{x\left(x+3\right)}\)

\(=\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.10}+\frac{1}{10.13}+\frac{1}{x\left(x+3\right)}\)

\(=\frac{1}{3}\left(\frac{1}{1}-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+\frac{1}{10}-\frac{1}{13}+\frac{1}{x}-\frac{1}{x+3}\right)\)

\(=\frac{1}{3}\left(\frac{1}{1}-\frac{1}{13}+\frac{1}{x}-\frac{1}{x+3}\right)\)

\(=\frac{1}{3}\left(\frac{12}{13}+\frac{1}{x}-\frac{1}{x+3}\right)\)

\(=\frac{1}{3}.\frac{12}{13}+\frac{1}{3}.\frac{1}{x}-\frac{1}{3}.\frac{1}{x+3}\)

\(=\frac{4}{13}+\frac{1}{3x}-\frac{1}{3x+3}\)

\(=\frac{4}{13}+\frac{1}{3x}-\frac{1}{3x+3}\)

\(=\frac{4}{13}+\frac{1}{3x}=\frac{1}{3x+3}\)

\(=\frac{4}{13}+\frac{1}{3x}=\frac{1}{3x+3}\)

\(=\frac{4}{13}+\frac{1}{3x}=\frac{1}{3}.\frac{1}{x+3}\)

\(=\frac{4}{13}=\frac{1}{3}.\frac{1}{x+3}-\frac{1}{3x}\)

\(=\frac{4}{13}=\frac{1}{3}.\frac{1}{x+3}-\frac{1}{3}.\frac{1}{x}\)

\(=\frac{4}{13}=\frac{1}{3}\left(\frac{1}{x+3}-\frac{1}{x}\right)\)

\(=\frac{4}{13}:\frac{1}{3}=\frac{1}{x+1}-\frac{1}{x}\)

\(=\frac{12}{13}=\frac{1}{x+1}-\frac{1}{x}\)

\(=\frac{12}{13}=\frac{x-\left(x+1\right)}{\left(x+1\right)x}\)

\(=\frac{12}{13}=-\frac{1}{x^2+x}\)

\(\Leftrightarrow=12\left(x^2+x\right)=13.\left(-1\right)\)

\(=12\left(x^2+x\right)=-13\)

\(=x^2+x=-\frac{13}{12}\)

\(=x\left(x+1\right)=-\frac{13}{12}\)

.... Chiụ