We have the following line:
[tex]\begin{gathered} 2x-y=7 \\ y=2x-7 \end{gathered}[/tex]and we must determine the slope of its perpendicular line.
Slopes of two perpendicular lines, m1 and m2, have the following property:
[tex]m_1\cdot m_2=-1[/tex]Given the slope of the first line (the coefficient that multiplies the x):
[tex]m_1=2[/tex]and using the formula above for the slope of its perpendicular line, we get:
[tex]\begin{gathered} m_1\cdot m_2=-1 \\ m_2=-\frac{1}{m_1} \\ m_2=-\frac{1}{2} \end{gathered}[/tex]Answer
A. −1/2
