a) -12/27 = 3x-1/9
=> (-12).9 = 27.(3x-1)
=> -108 = 81x-27
=> 81x = -81
=>x=-1
Vậy x=-1.
b) 3-x/45 = 2/9 = 1/2y
=> 1) 3-x/45 = 2/9
=> 9(3-x)=45.2
=> 27-9x=90
=> 9x=-63
=> x=-7.
2) 2/9=1/2y
=> 2(2y)=9.1
=> 4.2y = 9
=> 2y = 9/4
=> y = 9/8
Vậy x=-7 ; y=9/8
~Hok tốt~
-12/27=3x-1/9
3x-1/9=-12/27
3x =-12/27 + 1/9
3x = -12/27 + 3/27
3x = -9/27 = -1/3
x = -1/3 : 3
x = -1/9
3-x/45=2/9=1/2y
3-x/45=2/9
x/45 =3 - 2/9
x/45 =25/9
x = 45:9x25
x = 125
1/2y=2/9
y = 2/9:1/2
y = 2/9x2/1
y = 4/9
#HOC_TOT_NHA><
đúng thì k mk nhaa