Bài 1. Tìm x, biết:
a) \(\left(x-\dfrac{3}{5}\right).\left(\dfrac{18}{5}-\dfrac{4}{5}x\right)=0\)
b) \(5x.\left(x-\dfrac{1}{3}\right)=0\)
c) \(\left(x+\dfrac{1}{4}\right).\left(x-\dfrac{3}{7}\right)=0\)
d) \(\left(x+\dfrac{5}{3}\right).\left(x-\dfrac{5}{4}\right)=0\)
e) \(\left(\dfrac{3}{4}x-\dfrac{9}{16}\right).\left(1,5+\dfrac{-3}{5}:x\right)=0\)
f) \(\left(2,4-3x\right).0,5=0\)
g) \(\left(\dfrac{2x}{3}-3\right).\left(-10+2x\right)=0\)
h) \(\left(x-\dfrac{3}{14}\right).\left(5x+\dfrac{5}{12}\right)=0\\ \)
i) \(\left(x:\dfrac{1}{3}-3\right).\left(x-\dfrac{2}{5}\right)=0\)
j) \(\left(\dfrac{-2}{15}-x\right).\left(3x-\dfrac{1}{4}\right)=0\)
`a)`
`(x-3/5 ).(18/5 -4/5 .x)=0`
`Th1`
`x-3/5=0`
`=>x=0+3/5`
`=>x=3/5`
`Th2`
`18/5-4/5 x = 0`
`=> 4/5 x = 18/5-0`
`=>4/5 x = 18/5`
`=>x= 18/5 : 4/5`
`=>x= 18/5 . 5/4`
`=>x=9/2`
`b)`
`5x. (x-1/3)=0`
`Th1`
`5x=0`
`=>x=0:5`
`=>x=0`
`Th2`
`x-1/3=0`
`=>x=0+1/3`
`=>x=1/3`
`c)`
`(x+1/4) . (x-3/7)=0`
`Th1`
`x+1/4=0`
`=>x= 0-1/4`
`=>x=-1/4`
`Th2`
`x-3/7=0`
`=>x=0+3/7`
`=>x=3/7`
`d)`
`(x+5/3).(x- 5/4)=0`
`Th1`
`x+5/3=0`
`=>x=0-5/3`
`=>x=-5/3`
`Th2`
`x-5/4=0`
`=>x=0+5/4`
`=>x=5/4`
