6 The plane \(\Pi _ { 1 }\) has equation \(\mathbf { r } = \left( \begin{array} { l } 2
2
1 \end{array} \right) + \lambda \left( \begin{array} { l } 1
1
0 \end{array} \right) + \mu \left( \begin{array} { r } 1
- 5
- 2 \end{array} \right)\).
- Express the equation of \(\Pi _ { 1 }\) in the form r.n \(= p\).
The plane \(\Pi _ { 2 }\) has equation \(\mathbf { r } . \left( \begin{array} { r } 7
17
- 3 \end{array} \right) = 21\). - Find an equation of the line of intersection of \(\Pi _ { 1 }\) and \(\Pi _ { 2 }\), giving your answer in the form \(\mathbf { r } = \mathbf { a } + t \mathbf { b }\).