фы

\xx\\
\ell_1(t) =
 \begin{pmatrix}
  5\\
  -3 \\
  5 \\
 \end{pmatrix}
\cdot t+
\begin{pmatrix}
  7\\
  -2 \\
  7 \\
 \end{pmatrix}
\implies
\ell_1(t) =
 \begin{pmatrix}
  5t+7\\
  -3t-2 \\
  5t+7 \\
 \end{pmatrix}\\
\ell_2(s) =
 \begin{pmatrix}
  4\\
  -5 \\
  0 \\
 \end{pmatrix}
\cdot s+
\begin{pmatrix}
  10\\
  -9 \\
  \lambda \\
 \end{pmatrix}
\implies
\ell_2(s) =
 \begin{pmatrix}
  4s+10\\
  -5s-9 \\
  \lambda \\
 \end{pmatrix}
\\
\begin{cases}
    5t+7=4s+10\\
    -3t-2=-5s-9\\
5t+7=\lambda
  \end{cases}\\
\begin{cases}
    5t+7=4s+10\\
    -3t-2=-5s-9\\
  \end{cases}\implies
\begin{cases}
    5t-4s=3\\
    -3t+5s=-7\\
  \end{cases}\\
+\begin{cases}
    5t-4s=3 & \quad |\cdot5\\
    -3t+5s=-7 & \quad |\cdot4\\
  \end{cases}\\
5(5t−4s)+4(−3t+5s)=5 \cdot 3+4 \cdot (−7) \\
13t=−13 \\
t=−1\\
5(−1)−4s=3\\
s=−2\\
5(-1)+7=\lambda\\
\lambda=2