4 3/8÷5 1/4=х÷12 3 (2/5х+3)-3/5х=8

1) 4 3/8 : 5 1/4 = х : 123;

(4 * 8 + 3)/8 : (5 * 4 + 1)/4 = х : 123;

(32 + 3)/8 : (20 + 1)/4 = х : 123;

35/8 : 21/4 = х : 123;

35/8 * 4/21 * 123 = х;

х = (35 * 4 * 123)/(8 * 21) = 205/2.

2) (2/5 * х + 3) - 3/5 * х = 8;

(2 - 3)/5 * х = 8 - 3;

-1/5 * х = 5;

х = 5 * (-5) = -25.