Question Number 104141 by bobhans last updated on 19/Jul/20
Answered by bramlex last updated on 19/Jul/20
$$\left[\:\mathrm{1}\:\:\:{x}\:\:\:\mathrm{2}\:\right]\:\begin{bmatrix}{\mathrm{2}{x}+\mathrm{2}}\\{\:\:\:\:\:\:\mathrm{2}}\\{\:\:\:\:\:\:\mathrm{1}}\end{bmatrix}=\:\mathrm{0} \\ $$$$\Rightarrow\:\mathrm{2}{x}+\mathrm{2}\:+\mathrm{2}{x}\:+\:\mathrm{2}\:=\:\mathrm{0} \\ $$$$\mathrm{4}{x}\:=\:−\mathrm{4}\:\Rightarrow{x}\:=\:−\mathrm{1}\: \\ $$