Explanation
Given a complex number of the form a +bi we can find the absolute value as:
[tex]|a+bi|=\sqrt[]{a^2+b^2}[/tex]
In the question, we are asked to find the absolute value of -7+i. Therefore we can solve as;
[tex]\begin{gathered} |-7+i|=\sqrt[]{(-7)^2+1^2}=\sqrt[]{49+1}=\sqrt[]{50} \\ =\sqrt[]{25\times2} \\ =5\sqrt[]{2} \end{gathered}[/tex]
Answer:
[tex]5\sqrt[]{2}[/tex]
