TeX Quellcode:

\begin{array}{rcll}f\left(-\dfrac{11}{4}\right) &=& -2\cdot\sqrt{-\dfrac{11}{4}+15}+7 \\ \\&=& -2\cdot\sqrt{\dfrac{49}{4}}+7 \\ \\&=& -2\cdot\dfrac{7}{2}+7 \\ \\&=& 0\end{array}