Tìm x

a,2x - 2/5 = 4/7 : 5/1
b,5 mũ x-1 = 125
c(2/3) mũ x+1 = 8/27
d,|x+2/5|=3/4:5/8
_____________________
a,50% + 3/4 - 2/5
b,25% - 2/3 + 75%
c, 2/7 _ 3/4 : 5/8 + 7/10
4/9 : 5/6 _ 2/7 . _14/9