Answer: \(\lg\left(\frac{100x^3}{y}\right)\).

Use the logarithm rules

\(a\lg x=\lg x^a,\qquad \lg A+\lg B=\lg(AB),\qquad \lg A-\lg B=\lg\left(\frac{A}{B}\right).\)

Also,

\(2=\lg100.\)

Therefore

\(3\lg x+2-\lg y =\lg x^3+\lg100-\lg y.\)

So the expression is

\(\lg\left(\frac{100x^3}{y}\right).\)