a, 1 x 3 x 5 x 7 = ??
b, \(\frac{1}{5}\times\frac{1}{8}=??\)
Bài 15: Tìm x biết:
a, \(-\frac{3}{5}\times x=\frac{1}{4}+0,75\)
b, \(\left(\frac{1}{7}-\frac{1}{3}\right)\times x=\frac{28}{3}\times\left(\frac{1}{4}-\frac{1}{7}\right)\)
c, \(\frac{5}{7}\times x=\frac{9}{8}-0,125\)
d, \(\left(\frac{2}{11}+\frac{1}{3}\right)\times x=\left(\frac{1}{7}-\frac{1}{8}\right)\times36\)
\(a,\)\(-\frac{3}{5}\cdot x=\frac{1}{4}+0,75\)
\(-\frac{3}{5}\cdot x=\frac{1}{4}+\frac{3}{4}=\frac{4}{4}=1\)
\(x=1\div\left(-\frac{3}{5}\right)\)
\(x=-\frac{5}{3}\)
\(b,\)\(\left(\frac{1}{7}-\frac{1}{3}\right)\cdot x=\frac{28}{5}\times\left(\frac{1}{4}-\frac{1}{7}\right)\)
\(\left(\frac{3}{21}-\frac{7}{21}\right)\cdot x=\frac{28}{5}\cdot\left(\frac{7}{28}-\frac{4}{28}\right)\)
\(-\frac{4}{21}\cdot x=\frac{28}{5}\cdot\frac{3}{28}\)
\(-\frac{4}{21}\cdot x=\frac{3}{5}\)
\(x=\frac{3}{5}\div\left(-\frac{4}{21}\right)\)
\(x=-\frac{63}{20}\)
\(c,\)\(\frac{5}{7}\cdot x=\frac{9}{8}-0,125\)
\(\frac{5}{7}\cdot x=\frac{9}{8}-\frac{1}{8}\)
\(\frac{5}{7}\cdot x=1\)
\(x=1\div\frac{5}{7}\)
\(x=\frac{7}{5}\)
\(d,\)\(\left(\frac{2}{11}+\frac{1}{3}\right)\cdot x=\left(\frac{1}{7}-\frac{1}{8}\right)\cdot36\)
\(\left(\frac{6}{33}+\frac{11}{33}\right)\cdot x=\left(\frac{8}{56}-\frac{7}{56}\right)\cdot36\)
\(\frac{17}{33}\cdot x=\frac{1}{56}\cdot36\)
\(\frac{17}{33}\cdot x=\frac{9}{14}\)
\(x=\frac{9}{14}\div\frac{17}{33}\)
\(x=\frac{9}{14}\cdot\frac{33}{17}=\frac{297}{238}\)
a)\(\frac{3}{5}\times x=1\)
\(x=1\div\frac{3}{5}\)
\(x=\frac{5}{3}\)
Mình chỉ làm duoc câu a thôi
Tìm x biết:
a)\(\frac{3}{5}\times x-\frac{1}{5}=\frac{4}{5}\)
b)\(\frac{4}{7}+\frac{5}{7}\div x=1\)
c)\(\frac{-12}{7}\times\left(\frac{3}{4}-x\right)\times\frac{1}{4}=-1\)
d)\(x\div\frac{17}{8}=\frac{-2}{5}\times\frac{-9}{17}+3\)
a) \(\frac{3}{5}.x-\frac{1}{5}=\frac{4}{5}\)
\(\Leftrightarrow\frac{3}{5}.x=\frac{4}{5}+\frac{1}{5}\)
\(\Leftrightarrow\frac{3}{5}.x=1\)
\(\Leftrightarrow x=1:\frac{3}{5}\)
\(\Leftrightarrow x=\frac{5}{3}\)
Vậy : \(x=\frac{5}{3}\)
b) \(\frac{4}{7}+\frac{5}{7}:x=1\)
\(\Leftrightarrow\frac{5}{7}:x=1-\frac{4}{7}\)
\(\Leftrightarrow\frac{5}{7}:x=\frac{3}{7}\)
\(\Leftrightarrow x=\frac{5}{7}:\frac{3}{7}\)
\(\Leftrightarrow x=\frac{5}{3}\)
Vậy : \(x=\frac{5}{3}\)
c) \(-\frac{12}{7}.\left(\frac{3}{4}-x\right).\frac{1}{4}=-1\)
\(\Leftrightarrow\frac{-12.1}{7.4}.\left(\frac{3}{4}-x\right)=-1\)
\(\Leftrightarrow-\frac{3}{7}.\left(\frac{3}{4}-x\right)=-1\)
\(\Leftrightarrow\frac{3}{4}-x=-1:\left(-\frac{3}{7}\right)\)
\(\Leftrightarrow\frac{3}{4}-x=\frac{7}{3}\)
\(\Leftrightarrow x=\frac{3}{4}-\frac{7}{3}=-\frac{19}{12}\)
Vậy : \(x=-\frac{19}{12}\)
d) \(x:\frac{17}{8}=-\frac{2}{5}.-\frac{9}{17}+3\)
\(\Leftrightarrow x:\frac{17}{8}=\frac{273}{85}\)
\(\Leftrightarrow x=\frac{273}{85}.\frac{17}{8}\)
\(\Leftrightarrow x=\frac{273}{40}\)
Vậy : \(x=\frac{273}{40}\)
\(\)
Tìm x, biết:
a) \(\frac{4}{7}\times x-\frac{2}{3}=\frac{1}{5}\)
b) \(\frac{2}{9}-\frac{7}{8}\times x=\frac{1}{3}\)
c) \(\frac{4}{5}+\frac{5}{7}\div x=\frac{1}{6}\)
\(\frac{4}{7}\times x=\frac{1}{5}+\frac{2}{3}\)
\(\frac{4}{7}x=\frac{13}{15}\)
\(\Rightarrow x=\frac{91}{60}\)
các bài còn lại tương tự nha
mấy cái này dễ mà toán tìm x này là cơ bản!!
67865785685685785785774677567568568
\(\frac{4}{7}\times x-\frac{2}{3}=\frac{1}{5}\)
\(\frac{4}{7}\times x=\frac{2}{3}+\frac{1}{5}\)
\(\frac{4}{7}\times x=\frac{13}{15}\)
\(x=\frac{13}{15}\div\frac{4}{7}\)
\(x=\frac{91}{60}\)
bài 1 tìm x
\(x-25\%x=\frac{1}{2}\)
bài 2 tính hợp lý
\(a,(\frac{-4}{5}+\frac{4}{3})+(\frac{-5}{4}+\frac{14}{5})-\frac{7}{3}\) \(b,\frac{8}{3}\times\frac{2}{5}\times\frac{3}{10}\times10\times\frac{19}{92}\)\(c,\frac{-5}{7}\times\frac{2}{11}+\frac{-5}{7}\times\frac{9}{14}+1\frac{5}{7}\)
Bài 1: Tìm \( x \)
\[
x - \frac{25\%}{100}x = \frac{1}{2}
\]
Để giải phương trình này, trước hết chúng ta phải chuyển đổi phần trăm thành dạng thập phân:
\[
\frac{25\%}{100} = 0.25
\]
Phương trình ban đầu trở thành:
\[
x - 0.25x = \frac{1}{2}
\]
Tổng hợp các hạng tử giống nhau:
\[
1x - 0.25x = \frac{1}{2}
\]
\[
0.75x = \frac{1}{2}
\]
Giải phương trình ta được:
\[
x = \frac{\frac{1}{2}}{0.75} = \frac{2}{3}
\]
Vậy, \( x = \frac{2}{3} \)
Bài 2: Tính hợp lý
a) \[
\frac{5}{-4} + \frac{3}{4} + \frac{4}{-5} + \frac{14}{5} - \frac{7}{3}
\]
Chúng ta cần tìm một mẫu số chung cho tất cả các phân số. Mẫu số chung nhỏ nhất là 60.
\[
= \frac{75}{-60} + \frac{45}{60} + \frac{-48}{60} + \frac{168}{60} - \frac{140}{60}
\]
\[
= \frac{75 + 45 - 48 + 168 - 140}{60}
\]
\[
= \frac{100}{60} = \frac{5}{3}
\]
b) \[
\frac{8}{3} \times \frac{2}{5} \times \frac{3}{10} \times \frac{10}{92} \times \frac{19}{92}
\]
Tích của các phân số là:
\[
= \frac{8 \times 2 \times 3 \times 10 \times 19}{3 \times 5 \times 10 \times 92 \times 92}
\]
\[
= \frac{9120}{4131600} = \frac{57}{25825}
\]
c) \[
\frac{5}{7} \times \frac{2}{11} + \frac{5}{7} \times \frac{9}{14} + \frac{1}{5}
\]
Tích của các phân số là:
\[
= \frac{10}{77} + \frac{45}{98} + \frac{1}{5}
\]
\[
= \frac{980}{7546} + \frac{3485}{7546} + \frac{15092}{75460}
\]
\[
= \frac{2507}{7546}
\]
Bài 1:Tìm x Biết
a\ \(x-\frac{10}{3}=\frac{7}{15}\times\frac{3}{5}\)
b\ \(x+\frac{3}{22}=\frac{27}{121}\times\frac{11}{9}\)
c\ \(\frac{8}{23}\times\frac{46}{24}-x=\frac{1}{3}\)
d\ \(1-x=\frac{49}{65}\times\frac{5}{7}\)
a) \(x-\frac{10}{3}=\frac{7}{15}\cdot\frac{3}{5}\) b) \(x+\frac{3}{22}=\frac{27}{121}\cdot\frac{11}{9}\)
\(\Leftrightarrow x-\frac{10}{3}=\frac{7}{25}\) \(\Leftrightarrow x+\frac{3}{22}=\frac{3}{11}\)
\(\Rightarrow x=\frac{7}{25}+\frac{10}{3}\) \(\Rightarrow x=\frac{3}{11}-\frac{3}{22}\)
\(x=\frac{271}{75}\) \(x=\frac{3}{22}\)
c) \(\frac{8}{23}.\frac{46}{24}-x=\frac{1}{3}\) d) \(1-x=\frac{49}{65}.\frac{5}{7}\)
\(\Leftrightarrow\frac{2}{3}-x=\frac{1}{3}\) \(\Leftrightarrow1-x=\frac{7}{13}\)
\(\Rightarrow x=\frac{2}{3}-\frac{1}{3}\) \(\Rightarrow x=1-\frac{7}{13}\)
\(x=\frac{1}{3}\) \(x=\frac{6}{13}\)
bài 1 : tìm x biết
a, \(\frac{2}{3}\times\left(x-\frac{5}{6}\right)+\frac{1}{4}=\frac{22}{9}\)
b, \(\frac{2}{3}:\frac{x}{5}=\frac{10}{21}\)
c, \(\frac{7}{3}:\frac{x}{5}=\frac{14}{15}\)
d, \(1-\left(5\frac{4}{9}\times x-7\frac{7}{18}\right):15\frac{3}{4}=0\)
bài 2 : tính gtri bt
a,\(\frac{8}{7}+\frac{1}{5}\times\frac{10}{9}\)
b, \(\frac{3}{2}+\left(\frac{9}{2}+\frac{2}{9}\right)\times\left(\frac{4}{3}-\frac{5}{4}\right)\)
!_ove
a) x = 99/20
b) x = 7
c) x = 2
( chỉ lm đc đến đó thui nk )
a) \(5\frac{8}{17}\div x+\frac{-1}{17}\div x+3\frac{1}{17}\div17\frac{1}{3}=\frac{4}{17}\)
b)\(\frac{1}{1\times4}+\frac{1}{4\times7}+\frac{1}{7\times10}+...+\frac{1}{x\times\left(x+3\right)}=\frac{6}{19}\)
a) \(5\frac{8}{17}:x+\frac{-1}{17}:x+3\frac{1}{17}:17\frac{1}{3}=\frac{4}{17}\)
\(\frac{93}{17}:x+\frac{-1}{17}:x+\frac{52}{17}:\frac{52}{3}=\frac{4}{17}\)
\(\left(\frac{93}{17}+\frac{-1}{17}\right):x+\frac{52}{17}.\frac{3}{52}=\frac{4}{17}\)
\(\frac{92}{17}:x+\frac{3}{17}=\frac{4}{17}\)
\(\frac{92}{17}:x=\frac{4}{17}-\frac{3}{17}\)
\(\frac{92}{17}:x=\frac{1}{17}\)
\(x=\frac{92}{17}:\frac{1}{17}\)
\(x=92\)
b) \(\frac{1}{1.4}+\frac{1}{4.7}+\frac{1}{7.10}+...+\frac{1}{x.\left(x+3\right)}=\frac{6}{19}\)
\(\frac{1}{3}.\left(1-\frac{1}{4}\right)+\frac{1}{3}.\left(\frac{1}{4}-\frac{1}{7}\right)+\frac{1}{3}.\left(\frac{1}{7}-\frac{1}{10}\right)+...+\frac{1}{3}.\left(\frac{1}{x}-\frac{1}{x+3}\right)=\frac{6}{19}\)
\(\frac{1}{3}.\left(1-\frac{1}{4}+\frac{1}{4}-\frac{1}{7}+\frac{1}{7}-\frac{1}{10}+...+\frac{1}{x}-\frac{1}{x+3}\right)=\frac{6}{19}\)
\(\frac{1}{3}.\left(1-\frac{1}{x+3}\right)=\frac{6}{19}\)
\(1-\frac{1}{x+3}=\frac{6}{19}:\frac{1}{3}\)
\(1-\frac{1}{x+3}=\frac{18}{19}\)
\(\frac{1}{x+3}=1-\frac{18}{19}\)
\(\frac{1}{x+3}=\frac{1}{19}\)
\(\Rightarrow x+3=19\)
\(\Rightarrow x=19-3\)
\(\Rightarrow x=16\)
tìm x,
a, \(2(x-3)-5\times(2x-4)=0\)
b,\(3+\frac{1}{x-8}=0\)
c,\(\frac{8}{3}-\frac{2x+3}{5}=-\frac{-7}{3}\)
d,\(\frac{1}{9}=\frac{5}{3x-5}=0\)
\(a,2\left(x-3\right)-5\left(2x-4\right)=0\)
=> \(2x-6-10x-20=0\)
=> \(\left(2x-10x\right)-\left(6+20\right)=0\)
=> \(-8x-26=0\)
=> \(-8x=26\)
=> \(x=26:-8=-\frac{13}{4}\)
Vậy \(x\in\left\{-\frac{13}{4}\right\}\)
\(b,3+\frac{1}{x-8}=0\)
=> \(\frac{1}{x-8}=0-3=-3\)
=> \(x-8=-\frac{1}{3}\)
=> \(x=-\frac{1}{3}+8=\frac{23}{3}\)
Vậy \(x\in\left\{\frac{23}{3}\right\}\)
\(c,\frac{8}{3}-\frac{2x+3}{5}=\frac{-7}{3}\)
=> \(15.\frac{8}{3}-15.\frac{2x+3}{5}=15.\frac{-7}{3}\)
Chiệt tiêu
=> \(5.8-3\left(2x+3\right)=5.\left(-7\right)\)
=> \(40-\left(6x+9\right)=-35\)
=> \(40-6x-9=-35\)
=>\(31=6x=-35\)
=> \(6x=41-\left(-35\right)=66\)
=> \(x=66:6=11\)
Vậy \(x\in\left\{11\right\}\)
\(d,\frac{1}{9}=\frac{5}{3x-5}=0\)
=> \(\frac{1}{9}=0\left(sai\right)\)
=> \(x\in\varnothing\)
Bài 1: Thực hiện phép tính
a) \(\frac{-5}{2}\times\frac{\left(-14\right)}{7}\)
b) \(\left(1-\frac{1}{4}\right)^2+|\frac{-5}{4}|+\frac{-7}{8}-\frac{9}{16}\)
Bài 2: Tìm x biết:
a) \(x+\frac{2}{5}=\frac{-4}{3}\)
b) \(|\frac{2}{3}-x|=\frac{6}{5}\)