Tìm x, biết a) (x - 2/5) : 2/3 = 3/4 b) (x + -3/4) - 1/2 = 2/3 . 3/5

a)x−25:23=34x−25=34.23x−25=12x=910

b)x+−34−12=23.35  x+−34−12=25x+−34=910x=3320

c)x−27=−914.−43x−27=67+) x−27=67x=87+) x−27=−67  x=−47