Ta có : 

\(\frac{6}{1.3.5}+\frac{6}{3.5.7}+...+\frac{6}{15.17.19}-x=1\)

\(\Leftrightarrow\)\(\frac{6}{4}\left(\frac{4}{1.3.5}+\frac{4}{3.5.7}+...+\frac{4}{15.17.19}\right)=x+1\)

\(\Leftrightarrow\)\(\frac{6}{4}\left(\frac{1}{1.3}-\frac{1}{3.5}+\frac{1}{3.5}-\frac{1}{5.7}+...+\frac{1}{15.17}-\frac{1}{17.19}\right)=x+1\)

\(\Leftrightarrow\)\(\frac{6}{4}\left(\frac{1}{3}-\frac{1}{323}\right)=x+1\)

\(\Leftrightarrow\)\(\frac{6}{4}.\frac{320}{969}=x+1\)

\(\Leftrightarrow\)\(\frac{160}{323}=x+1\)

\(\Leftrightarrow\)\(x=\frac{160}{323}-1\)

\(\Leftrightarrow\)\(x=\frac{-163}{323}\)

Vậy \(x=\frac{-163}{323}\)

Chúc bạn học tốt ~ 

\(a,TH1:x-2021=0=>x=2021\)

\(Th2:x-2022=0=>x=2022\)

Vậy \(x\in\left\{2021;2022\right\}\)

\(b,x\left(8-5\right)=1080\)

\(x.3=1080\)

\(x=360\)

\(c,x^3=216< =>6^3=216=>x=3\)

\(d,5^5=3125\)

a)  ( x- 2021) * ( x- 2022) = 0

=>  \(\orbr{\begin{cases}x-2021=0\\x-2022=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=2021\\x=2022\end{cases}}}\)

b)  b. 8x - 5x = 2022

=>  3x  =  2022

=>  x  =   674

c)  \(5\cdot x^3=1080\)

=>  \(x^3=216\)

=>  \(x^3=6^3\)

=>   x  =  6

d)   \(5^x=3125\)

=>    \(5^x=5^5\)

=>  x    =  5

a)\(37.24+37.76+63.79+63.21=37.\left(24+76\right)+63.\left(79+21\right)\)

\(=37.100+63.100\)

\(=\left(37+63\right).100\)

\(=100.100\)

\(=10000\)

b)\(27.\left(13+48\right)+27.\left(22+17\right)=27.\left(13+48+22+17\right)\)

\(=27.100\)

\(=2700\)

Woa,cảm ựn bạn nha,may quá mk làm đúng rồi

Bài 1:

A, 37.24+37.76+63.79+63.21

=37.(24+76)+63.(79+21)

=37.100+63.100

=(37+63).100

=100.100

=10000

B) 27.(13+48)+27.(22+17)

=27.(13+48+22+17)

=27.100

=2700

a c b a b a d d b b

Đặt A=1.2+2.3+3.4+...+99.100

=>3.A=1.2.3+2.3.3+3.4.3+...+99.100.3

=>3.A=1.2.(3-0)+2.3.(4-1)+3.4.(5-2)+...+99.100.(101-98)

=>3.A=1.2.3-0.1.2+2.3.4-1.2.3+3.4.5-2.3.4+...+99.100.101-98.99.100

=>3.A=99.100.101

=>3.A=999900

=>A=333300

Vậy 1.2+2.3+3.4+...+99.100=333300

câu hỏi hay......nhưng tui xin nhường cho các bn khác

Hãy tích đúng cho tui nha

THANKS

\(x\cdot\left(x-1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x=0\\x-1=0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=0\\x=1\end{cases}}\)

\(\left(x+1\right)\left(x-2\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x+1=0\\x-2=0\end{cases}\Leftrightarrow}\orbr{\begin{cases}x=-1\\x=2\end{cases}}\)

\(x\cdot\left(x-2\right)\left(x-3\right)=0\)

\(\Leftrightarrow\hept{\begin{cases}x=0\\x-2=0\\x-3=0\end{cases}}\Leftrightarrow\hept{\begin{cases}x=0\\x=2\\x=3\end{cases}}\)

Phần cuối thay dấu ngoặc nhọn bằng dấu ngoặc vuông nha .

a,

\(x\left(x-1\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x-1=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x=1\end{cases}}\)

vậy_

b,

\(\left(x+1\right)\left(x-2\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x+1=0\\x-2=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=-1\\x=2\end{cases}}\)

vậy_

c, x(x - 2)(x - 3) = 0

=> x = 0 hoặc x - 2 = 0 hoặc x - 3 = 0

=> x = 0 hoặc x = 2 hoặc x = 3

vậy_

63485624.8

a) 2021 + 2022 + 2023 + 2024 + 2025 + 2026 + 2027 + 2028 + 2029

= (2021 + 2029) + (2022 + 2028) + (2023 + 2027) + (2024 + 2026) + 2025

= 4050 + 4050 + 4050 + 4050 + 2025

= 4050.4 + 2025

= 16 200 + 2025 

= 18 225

b)

a) 2021+2022+2023+2024+2025+2026+2027+2028+2029
= (2021+2029)+(2022+2028)+(2023+2027)+(2024+2026)+2025
= 4050+4050+4050+4050+2025
= 18225

b) 30.40.50.60
= 10.3.10.4.10.5.10.6
= (10.10.10.10).(3.4.5.6)
= 1000.360
= 3600000