Question Number 138513 by mathlove last updated on 14/Apr/21
Answered by MJS_new last updated on 14/Apr/21
$${AB}+\mathrm{9}=\mathrm{3}\left({BA}\right) \\ $$$$\mathrm{10}{A}+{B}+\mathrm{9}=\mathrm{30}{B}+\mathrm{3}{A} \\ $$$${A}=\frac{\mathrm{29}{B}−\mathrm{9}}{\mathrm{7}}\:\Rightarrow\:{B}=\mathrm{2}\wedge{A}=\mathrm{7} \\ $$$$\mathrm{72}+\mathrm{9}=\mathrm{3}×\mathrm{27} \\ $$$${A}+{B}=\mathrm{9} \\ $$