\(\left(0,75-\frac{5}{6}x\right)^3=\frac{-27}{64}\)
Giúp mik vs ạ!! Tks🥺
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Áp dụng tính chất dãy tỉ số bằng nhau có:
x/2=y/3=x.y/2.3=216/6=36
x/2=36
x=72
y/3=36
y=108
\(a,\left(\frac{31}{20}-\frac{26}{45}\right)\cdot\left(\frac{-36}{35}\right)< x< \left(\frac{51}{56}+\frac{8}{21}+\frac{1}{3}\right)\cdot\frac{8}{13}\)
\(taco:\left(\frac{31}{20}-\frac{26}{45}\right)\cdot\left(\frac{-36}{35}\right)=\frac{35}{36}\cdot\frac{-36}{35}=-1\)
\(\left(\frac{51}{56}+\frac{8}{21}+\frac{1}{3}\right)\cdot\frac{8}{13}=\frac{13}{8}\cdot\frac{8}{13}=1\)
\(=>x=0\)
\(b,\frac{-5}{6}+\frac{8}{3}+\frac{29}{-3}< x< \frac{-1}{2}+2+\frac{5}{2}\)(dau <co dau gach ngang o duoi nha)
\(taco:\frac{-5}{6}+\frac{8}{3}+\frac{29}{-3}=\frac{-5}{6}+\frac{8}{3}+\frac{-29}{3}=\frac{-5}{6}+\frac{16}{6}+\frac{-58}{6}=\frac{-47}{6}=-7,8\)
\(\frac{-1}{2}+2+\frac{5}{2}=\frac{3}{2}+\frac{5}{2}=4\)
tu do \(=>x=-7,8;...;0;1;2;3;4\)
a) 3/x-7 = 27/135
3/x-7 = 3/15
x - 7 = 15
x = 15 + 7
x = 22
a) \(\frac{3}{x-7}=\frac{27}{135}\)
\(\Rightarrow\)\(\left(x-7\right).27=3.135\)
\(\Rightarrow\)\(\left(x-7\right).27=405\)
\(\Rightarrow\)\(x-7=15\)
\(\Rightarrow\)\(x=22\)
Vậy \(x=22\)
b ) \(71+65.4=\frac{x+140}{x}+260\)
\(71+260=\frac{x+140}{x}+260\)
\(331=\frac{x+140}{x}+260\)
\(331-260=\frac{x+140}{x}\)
\(71=\frac{x+140}{x}\)
\(71=\frac{x}{x}+\frac{140}{x}\)
\(71=1+\frac{140}{x}\)
\(70=\frac{140}{x}\)
\(x=140\div70\)
\(x=20\)
Vậy \(x=20\)
#TQY
\(\left(\frac{x}{x^2-64}+\frac{x-8}{x^2+8x}\right):\frac{2x-6}{x^2+8x}+\frac{x}{8-x}\)
\(=\left[\frac{x}{\left(x-8\right)\left(x+8\right)}+\frac{x}{x\left(x+8\right)}\right]:\frac{2x-6}{x^2+8x}+\frac{x}{8-x}\)
\(=\left[\frac{x^2}{x\left(x-8\right)\left(x+8\right)}+\frac{\left(x-8\right)^2}{x\left(x-8\right)\left(x+8\right)}\right]:\frac{2x-6}{x^2+8x}+\frac{x}{8-x}\)
\(=\frac{x^2+\left(x-8\right)^2}{x\left(x-8\right)\left(x+8\right)}.\frac{x\left(x+8\right)}{2x-6}+\frac{x}{8-x}\)
\(=\frac{x^2+\left(x-8\right)^2}{x-8}.\frac{1}{2x-6}+\frac{x}{8-x}\)
\(=\frac{x^2+\left(x-8\right)^2}{\left(x-8\right)\left(2x-6\right)}-\frac{x}{8-x}\)
\(=\frac{-10x+64}{\left(x-8\right)\left(2x-6\right)}\)(tới đây quy đồng tính dc rồi :> lười ghi tiếp lắm)
:D
a) \(\left(-\frac{3}{4}\right)^{3x-1}=\frac{-27}{64}\)
\(\Leftrightarrow\left(-\frac{3}{4}\right)^{3x-1}=\left(-\frac{3}{4}\right)^3\)
\(\Leftrightarrow3x-1=3\)
\(\Leftrightarrow3x=4\)
\(\Leftrightarrow x=\frac{4}{3}\)
b) Đề sai ! Sửa :
\(\left(\frac{4}{5}\right)^{2x+5}=\frac{256}{625}\)
\(\Leftrightarrow\left(\frac{4}{5}\right)^{2x+5}=\left(\frac{4}{5}\right)^4\)
\(\Leftrightarrow2x+5=4\)
\(\Leftrightarrow2x=-1\)
\(\Leftrightarrow x=-\frac{1}{2}\)
c) \(\frac{\left(x+3\right)^5}{\left(x+5\right)^2}=\frac{64}{27}\)
\(\Leftrightarrow\left(x+3\right)^3=\left(\frac{4}{3}\right)^3\)
\(\Leftrightarrow x+3=\frac{4}{3}\)
\(\Leftrightarrow x=-\frac{5}{3}\)
d) \(\left(x-\frac{2}{15}\right)^3=\frac{8}{125}\)
\(\Leftrightarrow\left(x-\frac{2}{15}\right)^3=\left(\frac{2}{15}\right)^3\)
\(\Leftrightarrow x-\frac{2}{15}=\frac{2}{15}\)
\(\Leftrightarrow x=\frac{4}{15}\)
\(\left(0,75-\frac{5}{6}x\right)^3=\frac{-27}{64}\)
\(\left(\frac{3}{4}-\frac{5}{6}x\right)^3=\left(\frac{-3}{4}\right)^3\)
\(\Rightarrow\)\(\frac{3}{4}-\frac{5}{6}x=\frac{-3}{4}\)
\(\Rightarrow\)\(\frac{5}{6}x=\frac{3}{2}\)
\(\Rightarrow\)\(x=\frac{9}{5}\)
\(\left(0,75+\frac{5}{6}x\right)^3=\frac{-27}{64}\)
\(\left(0,75+\frac{5}{6}x\right)^3=\left(-\frac{3}{4}\right)^3\)
\(\Rightarrow0,75+\frac{5}{6}x=-\frac{3}{4}\)
\(\frac{5}{6}x=-\frac{3}{4}-0,75\)
\(\frac{5}{6}x=-\frac{3}{2}\)
\(x=-\frac{3}{2}:\frac{5}{6}\)
\(x=-\frac{9}{5}\)