We know that the angle 2 and the anlge 4 are equal because of oposite angles so:
[tex]4x-28=3x-9[/tex]
and we can solve for x so:
[tex]\begin{gathered} 4x-3x=-9+28 \\ x=19 \end{gathered}[/tex]
So:
[tex]\angle2=\angle4=3(19)-9=48º[/tex]
Now we also know that angle 1 and 3 are equal and the sum of the internal angles must be:
[tex]\begin{gathered} 360=2(48)+2(y) \\ \frac{360-96}{2}=y \\ y=132 \end{gathered}[/tex]
So angle 1 is equal to 132º
