We are given \( \frac{x}{y} = 0.45 \), which implies \( x = 0.45y \).
Substitute \( x = 0.45y \) into the given expression:
\[
\frac{3y - 0.45y}{3y + 0.45y} + \frac{6}{23}
\]
Simplify the fractions:
\[
\frac{2.55y}{3.45y} + \frac{6}{23}
\]
Cancel out \( y \) from the numerator and denominator:
\[
\frac{2.55}{3.45} + \frac{6}{23}
\]
Now simplify \( \frac{2.55}{3.45} \):
\[
\frac{2.55}{3.45} = \frac{255}{345} = \frac{17}{23}
\]
So, the expression becomes:
\[
\frac{17}{23} + \frac{6}{23} = \frac{17 + 6}{23} = \frac{23}{23} = 1
\]
Thus, the value of the expression is \( 1 \).