1 способ.
33 * (3 1/3х - 1 1/4х) = 19
33 * (10/3х - 5/4х) = 19
33 * (40/12х - 15/12х) = 19
33 * 25/12х = 19
825/12х = 19
х = 19 : 825/12
х = 19 * 12/825
х = 228/825
х = 76/275
2 способ.
33 * (3 1/3х - 1 1/4х) = 19
33 * (10/3х - 5/4х) = 19
33 * (40/12х - 15/12х) = 19
40/12х - 15/12х = 19 : 33
25/12х = 19/33
х = 19/33 : 25/12
х = 19/33 * 12/25
х = (19*4)/(11*25)
х = 76/275