8. The straight line \(l _ { 1 }\) passes through the point \(A ( - 2,5 )\) and the point \(B ( 4,1 )\).
- Find an equation for \(l _ { 1 }\) in the form \(a x + b y = c\), where \(a , b\) and \(c\) are integers.
The straight line \(l _ { 2 }\) passes through \(B\) and is perpendicular to \(l _ { 1 }\).
- Find an equation for \(l _ { 2 }\).
Given that \(l _ { 2 }\) meets the \(y\)-axis at the point \(C\),
- show that triangle \(A B C\) is isosceles.