Step 1: The slope of the line \( x + y = 5 \) is \( -1 \), since it is in the form \( y = -x + 5 \).
Step 2: The slope of the line perpendicular to this will be the negative reciprocal of \( -1 \), which is \( 1 \).
Step 3: Using the point \( (1, 1) \) and the slope \( 1 \), the equation of the line is: \[ y - 1 = 1(x - 1) \quad \Rightarrow \quad y = x \]
Thus, the equation is \( x - y = 0 \).
If $ X = A \times B $, $ A = \begin{bmatrix} 1 & 2 \\-1 & 1 \end{bmatrix} $, $ B = \begin{bmatrix} 3 & 6 \\5 & 7 \end{bmatrix} $, find $ x_1 + x_2 $.