\(x\times1,2+x\times3,4+x\times5,4=7,8\)
\(x\times\left(1,2+3,4+5,4\right)=7,8\)
\(x\times10=7,8\)
\(x=7,8:10\)
\(x=0,78\)
Xx1,2+Xx3,4+Xx5,4=7,8
<=>Xx(1,2+3,4+5,4)=7,8
<=>Xx10=7,8
<=>X=7,8:10=0,78
`x xx 1,2 + x xx 3,4 + x xx 5,4 = 7,8`
`=>x xx ( 1,2 + 3,4 + 5,4 ) = 7,8`
`=>x xx (4,6+5,4) = 7,8`
`=>x xx 10 = 7,8`
`=>x = 7,8 : 10`
`=>x = 0,78`
Vậy `x=0,78`