bai 1 : tim x biet :
1)\(\frac{x-1}{18}=\frac{2}{3}\) 2)\(\frac{64-4.x}{16}=\frac{15}{4}\) 3)\(\frac{7}{8}=\frac{35}{2.x+2}\) 4)\(\frac{5}{6}=\frac{3.x+1}{30}\)
5)\(\frac{4}{5}=\frac{16}{25-x}\) 6)\(\frac{x}{15}=\frac{6}{x+1}\)
vd: 2/3 =x/12
3.x = 2.12
3.x = 24
x = 24 : 3
x = 8
vay x = 8
1. Câu tl lun nà ~
( x-1). 3= 18.2
(x-1). 3 = 36
(x-1) = 36:3
(x-1) = 12
x = 12+1
x = 13
2. Tl lun ó
(64-4x).4= 16.15
(64-4x).4= 240
(64-4x) = 240:4
60x = 60
x= 60:60
x= 1