1/4 ------------------+2/5=1/2 3/4x-1/2
1/4:(3/4х-1/2)+2/5=1/2 1/4:(3/4х-1/2)=1/2-2/5 1/4:(3/4х-1/2)=5/10-4/10 1/4:(3/4х-1/2)=1/10 3/4х-1/2=1/4:1/10 3/4х-1/2=5/2 3/4х=5/2+1/2 3/4х=6/2 =>3 х=3:3/4 х=4
спасибо вам огромное