Concept:
Three points are collinear if they lie on the same straight line. This means the slope between any two pairs of points must be equal (\( m_1 = m_2 \)). Alternatively, the area of the triangle formed by these three points must be zero.
Step 1: Equate the slopes.
Points are \( A(1, 0), B(0, 1), C(x, 8) \).
\[ \text{Slope of AB } (m_1) = \frac{1-0}{0-1} = -1 \]
\[ \text{Slope of BC } (m_2) = \frac{8-1}{x-0} = \frac{7}{x} \]
For collinearity, \( m_1 = m_2 \):
\[ -1 = \frac{7}{x} \]
Step 2: Solve for \( x \).
\[ -x = 7 \implies x = -7 \]