Question

X x 4,3+X x5,7 =54,3 

Answer 1

\(x\) x 10 = 54,3

\(x\)         = 54,3 : 10

\(x\)         = 5,43

Answer 2

\(x\times4,3+x\times5,7=54,3\\ x\times\left(4,3+5,7\right)=54,3\\ x\times10=54,3\\ x=54,3:10\\ x=5,43\)