(4=х):8=9 и (m:5+3)*6=48

(4 + х) : 8 = 9;

4 + х = 9 * 8;

4 + х = 72;

х = 72 - 4;

х = 68;

(4 + 68) : 8 = 9;

72 : 8 = 9;

9 = 9;

(m : 5 + 3) * 6 = 48;

(m : 5 + 3)  = 48 : 6;

m : 5 + 3 = 8;

m : 5 = 8 - 3;

m : 5 = 5;

m = 5 * 5;

m = 25;

(25 : 5 + 3) * 6 = 48;

(5 + 3) * 6 = 48;

8 * 6 = 48;

48 = 48.