`a ) x + 28 × x + 15 × x - x × 2 = 48,6 + 203,4`
`x × 1 + 28 × x + 15 × x - x × 2 = 252`
`( 1 + 28 + 15 - 2 ) × x = 252`
`42 × x = 252`
`x = 252 : 42`
`x = 6`
`b ) 6,28 × x + x × 3,72 = 182,4`
`( 6,28 + 3,72 ) × x = 182,4`
`10 × x = 182,4`
`x = 182,4 : 10`
`x = 18,24`
`c ) 34,8 : y = 10`
`y = 34,8 : 10`
`y = 3,48`
`#dtkc`