Answer:
[tex]\sqrt{53}[/tex]
Step-by-step explanation:
[tex]\begin{pmatrix}-2&-7\end{pmatrix}\\=\sqrt{\left(-2\right)^2+\left(-7\right)^2}\\\\[/tex]
Then you need to simplify:
[tex]=\sqrt{2^2+\left(-7\right)^2}\\=\sqrt{2^2+7^2}\\=\sqrt{4+7^2}\\=\sqrt{4+49}\\=\sqrt{53}[/tex]
