[tex]\text{Doua unghiuri vecine ale paralelogramului, sunt suplementare. } \\
M+N=180^o \\
M-N=20^o \\ ------------ ~adunam ~ecuatiile. \\
2M=200^o \\
\ \textless \ M= \frac{200}{2}=\boxed{100^o} \\
\ \textless \ N=180-100 = \boxed{80^o} \\
\ \textless \ P = \ \textless \ M = \boxed{100^o}~~~~~(fiind ~unghiuri~ opuse) \\
\ \textless \ Q = \ \textless \ N = \boxed{80^o}~~~~~(fiind ~unghiuri~ opuse)[/tex]