The sum of angles in a triangle is 180degrees.
Therefore,
[tex]\begin{gathered} x+2x+3x=180^0 \\ \text{this implies that} \\ 6x=180^0 \\ \text{Dividing through by 6, we have} \\ \frac{6x}{6}=\frac{180^0}{6} \\ \text{ Therefore,} \\ x=30^0 \end{gathered}[/tex]Hence,
[tex]2x=2\times30^0=60^0[/tex]and
[tex]3x=3\times30^0=90^0[/tex]