\(\overrightarrow{u_{\Delta1}}=\left(11;-12\right)\) ; \(\overrightarrow{u_{\Delta2}}=\left(12;11\right)\)
\(\Rightarrow\overrightarrow{u_{\Delta1}}.\overrightarrow{u_{\Delta2}}=11.12-12.11=0\)
\(\Rightarrow\Delta_1\perp\Delta_2\) (hiển nhiên chúng cắt nhau)