2 (0,3х+(1цел1/4)х) =0,5х+3,75
0,6х+2/1 ×( 5/4)х=0,5х+3,75
0,6х+2,5х-0,5х=3,75
2,6х=3,75
х=3,75÷2,6
х=375/260
х=75/52
х=1цел23/52
2ой способ
2 ((3/10)х+(5/4)х)=0,5х+3,75
2 (((12+50)/40)х)=0,5х+3,75
2×(62/40)х=0;5х+3,75
2/1 × (31/20)х=0,5х+3,75
(31/10)х=0,5х+3,75
3,1х-0,5х=3,75
2,6х=3,75
х=375/260
х=1цел23/52