a) (5x + 2)/x
x =/ 0
D = R - {0}
b) x/x-1
x - 1 =/ 0
x =/ 1
D = R - {1}
c) 8x(2+x) / (x-3)(x+2)
x-3=/ 0
x=/ 3
x+2=/0
x=/-2
D = R - {3,-2}
d) 2/4x = 1/2x
2x =/ 0
x=/ 0
D = R - {0}
e) 3(x-1) / x-1 = 3
x-1 =/ 0
x=/ 1
D = R - {1}
f) (x^2 + x)/x = x(x + 1)/x = x + 1
x =/ 0
D = R -{0}