use the property, sum of the angles in the triangle is 180 degrees.
Thus, add all the angles,
we get,
[tex]\begin{gathered} x+\mleft(2x+5\mright)+\mleft(3x+7\mright)=180 \\ x+2x+5+3x+7=180 \\ x+2x+3x+5+7=180 \\ 6x+5+7=180 \\ 6x+12=180 \\ 6x=168 \\ \frac{6x}{6}=\frac{168}{6} \\ x=28 \end{gathered}[/tex]
Hence the value of x= 28
