Answer
$\frac{2b^{2}-3ab+4a^{2}}{a^{2}b^{2}}$
Work Step by Step
We form a common denominator:
$\displaystyle \frac{2}{a^{2}}-\frac{3}{ab}+\frac{4}{b^{2}}=\frac{2b^{2}}{a^{2}b^{2}}-\frac{3ab}{a^{2}b^{2}}+\frac{4a^{2}}{a^{2}b^{2}}=\frac{2b^{2}-3ab+4a^{2}}{a^{2}b^{2}}$
