Дам 52 б.

1) 1/x+3:2 2/5=3/4

2) 1/x-2:4 2/3x=2/7

1)

(1/x+3) / 2*2/5=3/4

(1/x+3) * 5/12=3/4 |12 (x+3)

12*5 (x+3) = 9 (x+3)

60x+180=9x+27

60x-9x=27-180

51x=-153

x=-153/51

x=-3

2)

(1/x-2) / 4*2/3x=2/7

(1/x-2) * 3/14x=2/7 |14x (x-2)

14x*3 (x-2) = 4x (x-2)

42x (x-2) = 4x^2-8x

42x^2-84x=4x^2-8x

42x^2-4x^2=-8x+84x

38x^2=76x

38x^2-76x=0

38x (x-2) = 0

x1=0

x2=2