[tex]\begin{gathered} 2x+30+2x-10=180 \\ 2x+2x+30-10=180 \\ 4x+20=180 \\ 4x=160 \\ x=\frac{160}{4} \\ x=40^0 \end{gathered}[/tex]
Let us find the angles of the parallelogram below
[tex]\begin{gathered} 2x+30 \\ x=40 \\ 2(40)+30 \\ 80+30 \\ 110^0 \end{gathered}[/tex][tex]\begin{gathered} 2x-10 \\ 2(40)-10 \\ 80-10 \\ 70^0 \end{gathered}[/tex]
Theorem+: opposite angles of a parallelogram are the same
Hence the angles of the parallelogram are 110, 70, 110, and 70
