Solution
= Solution
\b[No.] The nonzero <vector> $v=(2,-9,-3,21)^\top$ is in the kernel of the <linear map>, so $T(v)=T(0)=0$ although $v\ne0$. A <linear map> is <injective> exactly when its kernel consists only of zero.
= Solution
\b[No.] The nonzero <vector> $v=(2,-9,-3,21)^\top$ is in the kernel of the <linear map>, so $T(v)=T(0)=0$ although $v\ne0$. A <linear map> is <injective> exactly when its kernel consists only of zero.