Đáp án:
Giải thích các bước giải:
a) ( x - 1 )/( x + 5 ) = 7/9
<-> ( x - 1 ) . 9 = ( x + 5 ) . 7
<-> 9x - 9 = 7x + 35
<-> 9x-7x=9+35
<->2x=44
<-> x = 22
b) x^2/6 = 24/25
<-> x^2 . 25 = 6 . 24
<-> x^2 . 25 = 144
<-> x^2 .5^2=12^2 =(-12)^2
<-> x = 12/5 và x=-12/5
c) ( x - 2 )/( x - 1 ) = ( x + 4 )/( x + 7 )
<-> ( x - 2 )( x + 7 ) = ( x - 1 )( x + 4 )
<-> x^2 + 7x - 2x - 14 = x^2 + 4x - x - 4
<-> 5x - 14 = 3x - 4
<-> 2x = 10
<-> x = 5
d) ( x - 3 )/( x + 5 ) = 5/7
<-> ( x - 3 ) . 7 = ( x + 5 ) . 5
<-> 7x - 21 = 5x + 25
<-> 2x = 46
<-> x = 23
g) ( x - 1 )/( x + 2 ) = ( x - 2 )/( x + 3 )
<-> ( x - 1 )( x + 3 ) = ( x + 2 )( x - 2 )
<-> x^2 - x + 3x - 3 = x^2 - 2^2
<-> 2x - 3 = - 4
<-> 2x = -1
<-> x = -1/2
