Sorry bn, mik năm nay mới có lớp 5 nên ko làm đc bài nèy nha !
\(x=\frac{5}{3a-4}\)
a) \(x=1\Rightarrow\frac{5}{3a-4}=1\)
=> 3a - 4 = 5
=> 3a = 9
=> a = 3
b) \(x=2\Rightarrow\frac{5}{3a-4}=2\)
=> 2( 3a - 4 ) = 5
=> 6a - 8 = 5
=> 6a = 13
=> a = 13/6
c) \(x=\frac{5}{2}\Rightarrow\frac{5}{3a-4}=\frac{5}{2}\)
=> 5/2( 3a - 4 ) = 5
=> 15/2a - 10 = 5
=> 15/2a = 15
=> a = 2
a)\(\frac{5}{3a}\)- 4 = 2 b) \(\frac{5}{3a}\)- 4= -2 c) \(\frac{5}{3a}\)- 4 = \(\frac{5}{2}\)
=> \(\frac{5}{3a}\)= 6 =>\(\frac{5}{3a}\)= 2 => \(\frac{5}{3a}\)= \(\frac{13}{2}\)
=> a =\(\frac{5}{18}\) => a=\(\frac{5}{6}\) => a=\(\frac{10}{39}\)
Em thay vào luôn đấy nhé
a, Ta có : \(\frac{5}{3a-4}=1\Leftrightarrow5=3a-4\)
\(\Leftrightarrow3a=9\Leftrightarrow a=3\)
b, Ta có : \(\frac{5}{3a-4}=-2\Leftrightarrow5=-6a+8\)
\(\Leftrightarrow-6a=-3\Leftrightarrow a=\frac{1}{2}\)
c, \(\frac{5}{3a-4}=\frac{5}{2}\Leftrightarrow5=\frac{15}{2}a-10\)
\(\Leftrightarrow\frac{15}{2}a=15\Leftrightarrow a=2\)