4x-3,42×10=65,6 ; (3a-15,66)×28=0 ; (17,4-5y)×15=3

4x=65.6+3.42×104x=65.6+34,24x=99.8X=99.8:4X=24.954×24.95-3.42×10=65.617.4×15-5y×15=3261-75y=3261-3=75y258=75yy=258:75y=3.44(17.4-5×3.44)×15=3(3a-15.66)×28=03a×28-15.66×28=084a-438.48=084a=438.48a=438.48:84a=5.22(3×5.22-15.66)×28=0