3/x=-2/10
làm hộ nhé
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
(2 giờ 18 phút x 9+2,3 giờ x 6+138 phút x 5) : 10
= ( 2,3 giờ x 9 + 2,3 giờ x 6 + 2,3 giờ ) : 10
= 2,3 giờ x ( 9 + 6 ) : 10
= 2,3 giờ x 15 : 10
= 34,5 giờ : 10
= 3,45 giờ
\(A=\dfrac{\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{10}}}{\dfrac{2}{2}+\dfrac{2}{2^2}+...+\dfrac{2}{2^{10}}}=\dfrac{\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{10}}}{2\left(\dfrac{1}{2}+\dfrac{1}{2^2}+...+\dfrac{1}{2^{10}}\right)}=\dfrac{1}{2}\)
A = \(\dfrac{\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+....+\dfrac{1}{2^{10}}}{\dfrac{2}{2}+\dfrac{2}{2^2}+\dfrac{2}{2^3}+...+\dfrac{2}{2^{10}}}\)
= \(\dfrac{\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{10}}}{2\left(\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^{10}}\right)}\)
= \(\dfrac{1}{2}\)
1.
=3/5x(3/7+4/7)+2/5x(13/9-4/9)
=3/5x1+2/5x1
=3/5+2/5
=1
2.Xx(3/4+4/5)=7/10
Xx31/20=7/10
X =7/10:31/20
X =14/31
\(\frac{3}{5}\cdot\frac{3}{7}+\frac{3}{5}\cdot\frac{4}{7}+\frac{2}{5}\cdot\frac{13}{9}-\frac{2}{5}\cdot\frac{4}{9}\)
\(=\frac{3}{5}\cdot\left(\frac{3}{7}+\frac{4}{7}\right)+\frac{2}{5}\cdot\left(\frac{13}{9}-\frac{4}{9}\right)\)
\(=\frac{3}{5}\cdot1+\frac{2}{5}\cdot1\)\(=\frac{3}{5}+\frac{2}{5}=1\)
_________________________________________
\(\frac{3}{4}\cdot x+\frac{4}{5}\cdot x=\frac{7}{10}\)
\(\left(\frac{3}{4}+\frac{4}{5}\right)\cdot x=\frac{7}{10}\)
\(\frac{31}{20}\cdot x=\frac{7}{10}\)
\(x=\frac{7}{10}:\frac{31}{20}\)
\(x=\frac{14}{31}\)
\(\dfrac{2}{x}=\dfrac{x}{8}\)
\(x\cdot x=2\cdot8=16\)
\(16=4\cdot4\) nên \(x=4\)
\(\dfrac{x}{3}=\dfrac{4}{y}\)
\(x\cdot y=4\cdot3=12\)
\(x=4;y=3\)
\(x=3;y=4\)
\(x=2;y=6\)
\(x=6;y=2\)
\(x=1;y=12\)
\(x=12;y=1\)
\(\dfrac{2}{x}=\dfrac{x}{8}\) nên \(2\times8=x\times x\)
\(\Rightarrow16=x\times x\)
\(\Rightarrow4\times4=x\times x\)
\(\Rightarrow x=4\)
Thay vào \(\dfrac{x}{3}=\dfrac{4}{y}\) \(\Rightarrow\dfrac{4}{3}=\dfrac{4}{y}\)
\(\Rightarrow4\times y=3\times4\)
\(\Rightarrow4\times y=12\)
\(\Rightarrow12\div4=3=y\)
Vậy x=4; y=3
Câu 1:
0,9 x 218 x 2 + 0,18 x 4290 + 0,6 x 353 x 3
= 9/10 x 436 + 9/50 x 4290 + 6/10 x 1059
= 9 x 43,6 + 9 x 85,8 + 6 x 105,9
= 3 x 130,8 + 3 x 257,4 + 3 x 211,8
= 3 x ( 130,8 + 257,4 + 211,8 )
= 3 x 600
= 1800
Câu 2:
3/4 x X + 1/2 x X - 15 = 35
X x ( 3/4 + 1/2 ) - 15 = 35
X x ( 3/4 + 1/2 ) = 50
X x 5/4 = 50
X = 40
VẬy X = 40
a) \(1+2+3+...+x=325\)
\(\dfrac{x\times\left(x+1\right)}{2}=325\)
\(x\times\left(x+1\right)=325\times2\)
\(x\times\left(x+1\right)=650\)
\(x\times\left(x+1\right)=25\times26\)
\(x=25\)
b) Bạn xem lại đề:
x=-30
chúc bannj học tốt
\(\frac{3}{x}=\frac{-2}{10}\)
\(\Leftrightarrow30=-2x\)
\(\Leftrightarrow x=-15\)
#H