Question 17: Calculate the value of the expression \(\begin{array}{l} B = \left( { – 2{x^2}{y^2} + x{y^2} – 6xy} \right) :\frac{1}{3}xy \end{array}\) at \(x=- \frac{1}{2}; y=1\)

\(\begin{array}{l} B = \left( { – 2{x^2}{y^2} + x{y^2} – 6xy} \right):\frac{1}{3} xy = – 2{x^2}{y^2}:\frac{1}{3}xy + x{y^2}:\frac{1}{3}xy – 6xy:\frac{1}{ 3}xy = – 6xy + 3y – 18 \end{array}\)

Replace \(x=- \frac{1}{2}; y=1\) in B we have

\(B = – 6\left( { – \frac{1}{2}} \right).1 + 3.1 – 18 = – 12\)