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\(a,2\frac{x}{7}=\frac{75}{35}\)
\(\frac{75}{35}=2\frac{5}{35}=2\frac{1}{7}\)
\(\Rightarrow x=1\)
\(b,47:4=...\left(+3\right)\)
\(\Rightarrow\left(47-3\right):4=11\)
\(\Rightarrow x=11\)
\(c,\frac{112}{5}=\frac{336}{15}=22\left(+6\right)\)
\(\Rightarrow x=22\frac{x=6}{15}\)
\(d,7,5x=\frac{75x}{100}:\left(9-6\frac{13}{21}\right)=2\frac{13}{25}\)
\(\frac{75x}{100}:\left(9-\frac{139}{21}\right)=\frac{63}{25}\)
\(\frac{75x}{100}:\frac{50}{21}=\frac{63}{25}\)
\(\Rightarrow\frac{63^3}{25^{\left(1\right)}}\cdot\frac{50^{\left(2\right)}}{21^1}=6=\frac{6}{1}\)
\(\Rightarrow\frac{6}{1}=\frac{600}{100}\)
Con d sai đề
a. \(\frac{1}{5}=0,2\)
\(\Rightarrow|x|=-0,2\)
b.\(\frac{x+9}{15}=\frac{3}{5}\)
\(\frac{9}{15}=\frac{3}{5}\Rightarrow\frac{x+9}{15}=\frac{9}{5}\)
\(\Rightarrow x=0\)
c. \(|x|=0,75=\frac{3}{4}\)
\(|x|=\frac{3}{4}\)
\(|x|=-0,75\)
d.\(\frac{x}{169}=\frac{10^4}{x}\)
\(\frac{x}{169}=\frac{10000}{x}\)
\(\Rightarrow x=-1300\)
\(\frac{x-1}{9}=\frac{8}{3}\Rightarrow\)\(\frac{x-1}{9}=\frac{24}{9}\Rightarrow x-1=24\)
x=24+1
x=25
Vậy x=25
\(\frac{x-1}{9}=\frac{8}{3}\)
\(\Leftrightarrow\left(x-1\right):9=\frac{8}{3}\)
\(\Leftrightarrow\left(x-1\right)=24\)
\(\Leftrightarrow x=24+1\)
\(\Leftrightarrow x=25\)
\(a,\frac{x+5}{20}=-\frac{5}{4}\)
\(\left(x+5\right):20=\frac{-5}{4}\)
\(x+5=-\frac{5}{4}\times20\)
\(x+5=-25\)
\(x=-25-5\)
\(x=-30\)
các câu khác thì theo đó tự làm nha
bn ơi các câu a, b thì mk làm đc nhưng vướng câu c đó bn ạ
a) \(4\frac{3}{x}=\frac{47}{x}\)
\(\Rightarrow\frac{4\times x+3}{x}=\frac{47}{x}\)
\(\Rightarrow4\times x+3=47\)
\(4\times x=47-3\)
\(4\times x=44\)
\(x=44:4=11\)
b) \(x\frac{x}{15}=\frac{112}{5}\)
\(\Rightarrow\frac{x\times15+x}{15}=\frac{336}{15}\)
\(\Rightarrow\frac{x\times16}{15}=\frac{336}{15}\)
\(\Rightarrow x\times16=336\)
\(x=21\)
Chúc bn học tốt!!!!
Ta có :
\(\frac{x-3}{y-2}=\frac{2}{3}\)\(\Rightarrow\)\(\frac{x-3}{2}=\frac{y-2}{3}\)
Áp dụng tính chất dãy tỉ số bằng nhau ta có :
\(\frac{x-3}{2}=\frac{y-2}{3}=\frac{x-3-\left(y-2\right)}{2-3}=\frac{x-3-y+2}{-1}=\frac{4-3+2}{-1}=\frac{3}{-1}=-3\)
Do đó :
\(\frac{x-3}{2}=-3\Rightarrow x=\left(-3\right).2+3=-6+3=-3\)
\(\frac{y-2}{3}=-3\Rightarrow y=\left(-3\right).3+2=-9+2=-7\)
Vậy \(x=-3\)và \(y=-7\)
Ta có \(\frac{x-3}{y-2}=\frac{2}{3}\)
\(\Rightarrow3.\left(x-3\right)=2.\left(y-2\right)\)
\(\Rightarrow3x-9=2y-4\) (1)
Từ x - y = 4 nên y = 4 + x . Thay y = 4 + x vào ( 1) ta có
\(3.\left(y+4\right)-9=2y-4\)
\(\Rightarrow3y+12-9=2y-4\)
\(\Rightarrow3y+3=2y-4\)
\(\Rightarrow3y-2y=-4-3\)
\(\Rightarrow y=-7\)
Do đó x = -3
Vậy x = -3 và y = -7
\(a,4\frac{3}{x}=\frac{47}{x}\)
\(\frac{4x+3}{x}=\frac{47}{x}\)
\(\Rightarrow4x^2+3x=47x\)
\(4x^2=47x-3x=44x\)
\(4x^2:4x=44x:4x\)
\(x=11\)
\(b,x\frac{x}{15}=\frac{112}{5}\)
\(\frac{15x+x}{15}=\frac{112}{5}\)
\(75x+5x=112.15\)
\(80x=1680\)
\(x=21\)
a, \(4\frac{3}{x}=\frac{47}{x}\)
\(\Leftrightarrow\frac{4x+3}{x}=\frac{47}{x}\)
\(\Leftrightarrow4x+3=47\)
\(4x=47-3\)
\(4x=44\)
\(x=44:4\)
\(x=11\)
b, \(x\frac{x}{15}=\frac{112}{5}\)
\(\Leftrightarrow\frac{15x+x}{15}=\frac{112}{5}\)
\(\Leftrightarrow\frac{16x}{15}=\frac{336}{15}\)
\(\Leftrightarrow16x=336\)
\(x=336:16\)
\(x=21\)